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Questions and Answers
What is the mean of the given test scores 92, 84, 65, 76, 88, 90?
What is the mean of the given test scores 92, 84, 65, 76, 88, 90?
The median is always higher than the mean in a data set with a positive skew.
The median is always higher than the mean in a data set with a positive skew.
False
How would you interpret the 75th percentile in a data set?
How would you interpret the 75th percentile in a data set?
It indicates that 75% of the data points are below that value.
The calculation of a Z-score indicates how many __________ a data point is from the mean.
The calculation of a Z-score indicates how many __________ a data point is from the mean.
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Match the following variables with their definitions:
Match the following variables with their definitions:
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What is used to measure the dispersion in a data set instead of the sum of the deviations?
What is used to measure the dispersion in a data set instead of the sum of the deviations?
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The sum of all deviations from the mean in any data set is greater than zero.
The sum of all deviations from the mean in any data set is greater than zero.
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What symbol is used to denote the standard deviation of a population?
What symbol is used to denote the standard deviation of a population?
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To calculate the standard deviation of a sample, you divide the sum of squared deviations by ______.
To calculate the standard deviation of a sample, you divide the sum of squared deviations by ______.
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Match each company with their standard deviation ranking based on battery hours:
Match each company with their standard deviation ranking based on battery hours:
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Given a sample with values {2, 4, 7, 12, 15}, what is the calculated standard deviation?
Given a sample with values {2, 4, 7, 12, 15}, what is the calculated standard deviation?
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A higher standard deviation indicates that the data points are closer to the mean.
A higher standard deviation indicates that the data points are closer to the mean.
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What is the primary purpose of calculating standard deviation in statistical analysis?
What is the primary purpose of calculating standard deviation in statistical analysis?
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What is the z-score for Raul's first test score of 72?
What is the z-score for Raul's first test score of 72?
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A z-score of 1.2 for a light bulb indicates that it has a lifespan shorter than the mean lifespan.
A z-score of 1.2 for a light bulb indicates that it has a lifespan shorter than the mean lifespan.
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What is the lifespan of the DuraBright Company's light bulb if its z-score is 1.2, with a mean of 842 hours and a standard deviation of 90?
What is the lifespan of the DuraBright Company's light bulb if its z-score is 1.2, with a mean of 842 hours and a standard deviation of 90?
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The pth percentile is defined as the value for which p% of the data values are _____ than x.
The pth percentile is defined as the value for which p% of the data values are _____ than x.
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Match the following z-scores with their corresponding interpretation:
Match the following z-scores with their corresponding interpretation:
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Which of the following statements is true about percentiles?
Which of the following statements is true about percentiles?
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In a distribution, if the mean and median are the same, the distribution is symmetrical.
In a distribution, if the mean and median are the same, the distribution is symmetrical.
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In 2021, the median annual salary for physical therapists was $74,480. What percent of physical therapists earn more than this amount?
In 2021, the median annual salary for physical therapists was $74,480. What percent of physical therapists earn more than this amount?
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What is the standard deviation of the sample consisting of the numbers 2, 4, 7, 12, and 15?
What is the standard deviation of the sample consisting of the numbers 2, 4, 7, 12, and 15?
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Variance is the square root of the standard deviation.
Variance is the square root of the standard deviation.
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What is the mean of the sample set consisting of the numbers 2, 4, 7, 12, and 15?
What is the mean of the sample set consisting of the numbers 2, 4, 7, 12, and 15?
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The variance is calculated by taking the ______ of the standard deviation.
The variance is calculated by taking the ______ of the standard deviation.
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Match each term to its correct definition:
Match each term to its correct definition:
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Which type of argument uses specific examples as premises to propose a general conclusion?
Which type of argument uses specific examples as premises to propose a general conclusion?
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An argument is valid if its conclusion is guaranteed under its given set of premises.
An argument is valid if its conclusion is guaranteed under its given set of premises.
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What is the conclusion in the deductive argument: 'All humans are mortal. Socrates is a human. Therefore, Socrates is mortal.'?
What is the conclusion in the deductive argument: 'All humans are mortal. Socrates is a human. Therefore, Socrates is mortal.'?
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An argument is __________ if it is not valid.
An argument is __________ if it is not valid.
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Match the following example with its type of argument:
Match the following example with its type of argument:
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What defines a deductive argument?
What defines a deductive argument?
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All arguments presented are valid if the conclusion does not follow from the premises.
All arguments presented are valid if the conclusion does not follow from the premises.
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What is the formula for calculating the range of a data set?
What is the formula for calculating the range of a data set?
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Classify the argument: 'All spicy foods give me indigestion. Chili is a spicy food. Therefore, chili gives me indigestion.'
Classify the argument: 'All spicy foods give me indigestion. Chili is a spicy food. Therefore, chili gives me indigestion.'
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The standard deviation is always less than the range of a data set.
The standard deviation is always less than the range of a data set.
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What does a larger standard deviation indicate about a data set?
What does a larger standard deviation indicate about a data set?
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To calculate the standard deviation of a sample, we use the symbol _____ to represent it.
To calculate the standard deviation of a sample, we use the symbol _____ to represent it.
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Match the statistical terms with their definitions:
Match the statistical terms with their definitions:
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Why is the sum of the deviations from the mean always zero?
Why is the sum of the deviations from the mean always zero?
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The range provides a complete measure of the dispersion of data in all cases.
The range provides a complete measure of the dispersion of data in all cases.
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In statistical terms, what does the symbol σ represent?
In statistical terms, what does the symbol σ represent?
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What is the sum of all deviations from the mean for any data set?
What is the sum of all deviations from the mean for any data set?
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The sample standard deviation is designated by the symbol s.
The sample standard deviation is designated by the symbol s.
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What is the standard deviation of the sample calculated from the numbers 2, 4, 7, 12, and 15?
What is the standard deviation of the sample calculated from the numbers 2, 4, 7, 12, and 15?
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The average of a set of numbers is also known as the __________.
The average of a set of numbers is also known as the __________.
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Match each company to its standard deviation ranking of their battery hours:
Match each company to its standard deviation ranking of their battery hours:
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In calculating the standard deviation, which value do you divide the sum of squared deviations by when working with a sample of n numbers?
In calculating the standard deviation, which value do you divide the sum of squared deviations by when working with a sample of n numbers?
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Variance is a statistic that is used to measure the central value of a dataset.
Variance is a statistic that is used to measure the central value of a dataset.
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What statistical measure is used to represent the average squared deviations from the mean?
What statistical measure is used to represent the average squared deviations from the mean?
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What is the first step in finding quartiles in a data set?
What is the first step in finding quartiles in a data set?
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The first quartile, Q1, is the median of the data values that are greater than Q2.
The first quartile, Q1, is the median of the data values that are greater than Q2.
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What is the formula to calculate the percentile of a score x?
What is the formula to calculate the percentile of a score x?
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In a normal distribution, a z-score of ______ indicates that a data point is above the mean.
In a normal distribution, a z-score of ______ indicates that a data point is above the mean.
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Match the following quartile definitions with their respective terms:
Match the following quartile definitions with their respective terms:
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If the 25th percentile for the annual salary of a police dispatcher is $32,761, what percentage of dispatchers earn less than this amount?
If the 25th percentile for the annual salary of a police dispatcher is $32,761, what percentage of dispatchers earn less than this amount?
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For the given data set of weights, the quartile values can be determined by simply averaging all values.
For the given data set of weights, the quartile values can be determined by simply averaging all values.
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What is the value of the second quartile, Q2, in a ranked set of data?
What is the value of the second quartile, Q2, in a ranked set of data?
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What is the standard deviation of the sample consisting of the numbers 2, 4, 7, 12, and 15?
What is the standard deviation of the sample consisting of the numbers 2, 4, 7, 12, and 15?
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Variance is the square root of the standard deviation.
Variance is the square root of the standard deviation.
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What is the variance of the sample if the standard deviation is 5.43?
What is the variance of the sample if the standard deviation is 5.43?
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To calculate the variance of a sample, you divide the sum of squared deviations by __________.
To calculate the variance of a sample, you divide the sum of squared deviations by __________.
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Match the following terms with their definitions:
Match the following terms with their definitions:
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What is the formula for calculating variance?
What is the formula for calculating variance?
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The standard deviation can be defined as the square of the variance.
The standard deviation can be defined as the square of the variance.
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If the standard deviation of a dataset is 4, what is the variance?
If the standard deviation of a dataset is 4, what is the variance?
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The z-score for a given data value x indicates how many __________ from the mean the data point is.
The z-score for a given data value x indicates how many __________ from the mean the data point is.
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Match the given standard deviation with its variance:
Match the given standard deviation with its variance:
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Which team demonstrates the least variation in player heights from the mean?
Which team demonstrates the least variation in player heights from the mean?
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A higher standard deviation indicates that data points are more spread out from the mean.
A higher standard deviation indicates that data points are more spread out from the mean.
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Calculate the variance of a sample with a standard deviation of 10.
Calculate the variance of a sample with a standard deviation of 10.
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In the argument represented symbolically by ~p → r, what does ~p signify?
In the argument represented symbolically by ~p → r, what does ~p signify?
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The conclusion of an argument is invalid if it is true when all premises are true.
The conclusion of an argument is invalid if it is true when all premises are true.
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What is represented by the symbol ∴ in logical arguments?
What is represented by the symbol ∴ in logical arguments?
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In symbolic logic, the statement 'Aristotle was human' is represented by the variable ______.
In symbolic logic, the statement 'Aristotle was human' is represented by the variable ______.
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Match each component of the argument to its appropriate description:
Match each component of the argument to its appropriate description:
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Which of the following represents the second premise in the argument about Aristotle's mortality?
Which of the following represents the second premise in the argument about Aristotle's mortality?
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Constructing a truth table is unnecessary when determining the validity of an argument.
Constructing a truth table is unnecessary when determining the validity of an argument.
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If the premises are true and the conclusion is false, the argument is considered ______.
If the premises are true and the conclusion is false, the argument is considered ______.
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What is the median of the list 46, 23, 92, 89, 77, 108?
What is the median of the list 46, 23, 92, 89, 77, 108?
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The mode is defined as the number that appears most frequently in a data set.
The mode is defined as the number that appears most frequently in a data set.
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What is the weighted mean of a student's scores if the weights of the scores are 1, 1, 1, and 2 for the final exam?
What is the weighted mean of a student's scores if the weights of the scores are 1, 1, 1, and 2 for the final exam?
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In a data set, if every number occurs only once, there is __________.
In a data set, if every number occurs only once, there is __________.
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What is the mode of the list 18, 15, 21, 16, 15, 14, 15, 21?
What is the mode of the list 18, 15, 21, 16, 15, 14, 15, 21?
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Match the following measures of central tendency with their definitions:
Match the following measures of central tendency with their definitions:
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The median is always the middle number in a dataset with an odd number of entries.
The median is always the middle number in a dataset with an odd number of entries.
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How is the median calculated in a data set with an even number of entries?
How is the median calculated in a data set with an even number of entries?
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What is the value of the first quartile (Q1) in the data set: 2, 5, 5, 8, 11, 12, 19, 22, 23, 29, 31, 45, 83, 91, 104, 159, 181, 312, 354?
What is the value of the first quartile (Q1) in the data set: 2, 5, 5, 8, 11, 12, 19, 22, 23, 29, 31, 45, 83, 91, 104, 159, 181, 312, 354?
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The median is considered the first quartile in a data set.
The median is considered the first quartile in a data set.
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What is the formula to calculate a percentile for a score?
What is the formula to calculate a percentile for a score?
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In a data set, the _______ divides the ranked data into four equal parts.
In a data set, the _______ divides the ranked data into four equal parts.
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Match each statistic with its definition:
Match each statistic with its definition:
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If Roland received a z-score of 0.6 with a mean score of 65.5, what can be inferred about his test score of 70?
If Roland received a z-score of 0.6 with a mean score of 65.5, what can be inferred about his test score of 70?
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The third quartile (Q3) represents the median of the upper half of the data values.
The third quartile (Q3) represents the median of the upper half of the data values.
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What is the 25th percentile in relation to a data set?
What is the 25th percentile in relation to a data set?
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What is the symbolic form of the argument presented?
What is the symbolic form of the argument presented?
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The argument is valid based on the truth table provided.
The argument is valid based on the truth table provided.
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What are the symbols used for 'I arrive before 8 A.M.' and 'I will make the flight'?
What are the symbols used for 'I arrive before 8 A.M.' and 'I will make the flight'?
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If I make the flight, then I will give the __________.
If I make the flight, then I will give the __________.
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Match the premises to their logical implications:
Match the premises to their logical implications:
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Which row in the truth table indicates a false conclusion?
Which row in the truth table indicates a false conclusion?
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The premises a → f and f → p lead to the conclusion a → p.
The premises a → f and f → p lead to the conclusion a → p.
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What does the conclusion a → p symbolize in the argument?
What does the conclusion a → p symbolize in the argument?
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In the symbolic form of the argument, 'If she doesn’t get on the plane, she will regret it. She doesn’t regret it. Therefore, she got on the plane,' what does ~p represent?
In the symbolic form of the argument, 'If she doesn’t get on the plane, she will regret it. She doesn’t regret it. Therefore, she got on the plane,' what does ~p represent?
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The conclusion of an argument is considered valid if it is true in every row of the truth table where all premises are true.
The conclusion of an argument is considered valid if it is true in every row of the truth table where all premises are true.
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What is the symbolic form of the argument 'If it rains, then the game will not be played. It is not raining. Therefore, the game will be played'?
What is the symbolic form of the argument 'If it rains, then the game will not be played. It is not raining. Therefore, the game will be played'?
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In logical expressions, the three dots ∴ represent __________.
In logical expressions, the three dots ∴ represent __________.
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Match the terms to their meanings:
Match the terms to their meanings:
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Which of the following statements expresses the first premise in the argument involving Aristotle?
Which of the following statements expresses the first premise in the argument involving Aristotle?
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A truth table must be constructed for every argument to assess its validity.
A truth table must be constructed for every argument to assess its validity.
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What is the logical conclusion drawn from the premises, 'If it rains, then the game will not be played. It is not raining.'?
What is the logical conclusion drawn from the premises, 'If it rains, then the game will not be played. It is not raining.'?
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Which type of reasoning is exemplified by the argument: If it is raining, then the grass is wet. It is not raining. Therefore, the grass is not wet?
Which type of reasoning is exemplified by the argument: If it is raining, then the grass is wet. It is not raining. Therefore, the grass is not wet?
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An argument is valid if its conclusion follows from the premises.
An argument is valid if its conclusion follows from the premises.
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What is the conclusion of the argument: 'If you helped solve the crime, then you should be rewarded. You helped solve the crime. Therefore, you should be rewarded.'?
What is the conclusion of the argument: 'If you helped solve the crime, then you should be rewarded. You helped solve the crime. Therefore, you should be rewarded.'?
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The argument structure 'c→s, s, ∴c' is identified as the __________.
The argument structure 'c→s, s, ∴c' is identified as the __________.
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Match each argument with its type of reasoning:
Match each argument with its type of reasoning:
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Which argument is an example of disjunctive reasoning?
Which argument is an example of disjunctive reasoning?
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The argument 'If you helped solve the crime, then you should be rewarded. You should be rewarded. Therefore, you helped solve the crime.' is valid.
The argument 'If you helped solve the crime, then you should be rewarded. You should be rewarded. Therefore, you helped solve the crime.' is valid.
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Identify whether the argument 'If the movie’s production costs exceed $50 million, then I want to see it. The production costs were less than $50 million. Therefore, I do not want to see it.' is valid or invalid.
Identify whether the argument 'If the movie’s production costs exceed $50 million, then I want to see it. The production costs were less than $50 million. Therefore, I do not want to see it.' is valid or invalid.
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What does the Greek letter sigma (Σ) signify in statistics?
What does the Greek letter sigma (Σ) signify in statistics?
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The mode is the value that occurs most frequently in a data set.
The mode is the value that occurs most frequently in a data set.
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What symbol is used to denote the mean of a sample?
What symbol is used to denote the mean of a sample?
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The __________ is the middle number in a ranked list of data.
The __________ is the middle number in a ranked list of data.
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Match the following statistical terms with their definitions:
Match the following statistical terms with their definitions:
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Which of the following statements is true regarding sample and population means?
Which of the following statements is true regarding sample and population means?
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The median can be found by ranking the numbers and selecting the highest value.
The median can be found by ranking the numbers and selecting the highest value.
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What is the meaning of the symbol μ in statistics?
What is the meaning of the symbol μ in statistics?
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Which form of reasoning can be applied to the argument: 'If I have a cold, then I find it difficult to sleep. I find it difficult to sleep. ∴ I have a cold.'?
Which form of reasoning can be applied to the argument: 'If I have a cold, then I find it difficult to sleep. I find it difficult to sleep. ∴ I have a cold.'?
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The argument 'The program is interesting, or I will watch the basketball game. The program is not interesting. ∴ I will watch the basketball game' is valid.
The argument 'The program is interesting, or I will watch the basketball game. The program is not interesting. ∴ I will watch the basketball game' is valid.
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What can be concluded from the premises 'If they eat (f), they will go back (b)' and 'If they go back (b), they will have a party (p)'?
What can be concluded from the premises 'If they eat (f), they will go back (b)' and 'If they go back (b), they will have a party (p)'?
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If the argument structure is p → q, and q is true, then the conclusion drawn is ______.
If the argument structure is p → q, and q is true, then the conclusion drawn is ______.
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Match the following logical forms with their validity:
Match the following logical forms with their validity:
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Which type of reasoning uses the form p ∨ q?
Which type of reasoning uses the form p ∨ q?
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The Fallacy of the Inverse involves the form p → q leading to ∴ ~p.
The Fallacy of the Inverse involves the form p → q leading to ∴ ~p.
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Identify the premises in the argument: 'If you can dream it (p), you can do it (q). You can dream it (p).'
Identify the premises in the argument: 'If you can dream it (p), you can do it (q). You can dream it (p).'
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Study Notes
Z-Score
- Z-score is a standardized score that tells us how many standard deviations a data point is from the mean.
- Formula: Z = (x-μ)/σ for population and Z = (x-x̄)/s for sample.
- Z-score helps compare data points from different distributions.
Example 1
- Raul scored 72 on a test with a mean of 65 and standard deviation of 8.
- His Z-score is 0.875.
- Raul scored 60 on another test with a mean of 45 and standard deviation of 12.
- His Z-score is 1.25.
- Raul performed better on the second test compared to other students.
Example 2
- A consumer group tested 100 light bulbs, finding a mean life of 842 hours and a standard deviation of 90 hours.
- One bulb had a Z-score of 1.2.
- Plugging Z-score into the formula, we find the bulb had a lifespan of 950 hours.
Percentiles
- A percentile is a value below which a certain percentage of data points fall.
- Example: The 90th percentile for physical therapist salaries means 90% of physical therapists earn less than that salary.
- Median is the 50th percentile.
- To find the percentile of a single data point, divide the number of data points below that value by the total number of data points, then multiply by 100.
Standard Deviation
- Standard deviation measures how spread out data points are from the mean.
- It uses the sum of squared deviations from the mean.
- Sample standard deviation (s) is used when working with a subset of data, while population standard deviation (σ) is for the entire population.
Calculating Standard Deviation
- Step 1: Find the mean of the data set.
- Step 2: Calculate the deviation of each data point from the mean.
- Step 3: Square each deviation and sum them.
- Step 4: Divide the sum of squared deviations by (n-1) for a sample, where n is the sample size.
- Step 5: Take the square root of the result from Step 4.
Example 3
- A consumer group tested 8 batteries from 3 different companies.
- The standard deviation for each company's batteries helps determine which company produces batteries with the most consistent performance.
Variance
- Variance is another measure of dispersion, calculated as the square of the standard deviation.
- It is also used to understand the spread of data points around the mean.
Frequency Distribution
- A frequency distribution table lists observed events and the number of times they occur.
- It helps organize raw data and provides a clearer picture of the data's frequency distribution.
Arguments in Symbolic Form
- An argument consists of a series of statements that lead to a conclusion
- Arguments can be written in symbolic form to make their logic easier to see
- An argument is valid if the conclusion is true whenever all the premises are assumed to be true
- An argument is invalid if it is not a valid argument
Types of Arguments
- Inductive argument: Uses specific examples to make a general conclusion (from specific to general)
- Deductive argument: Uses general statements to make a specific conclusion (from general to specific)
Measures of Dispersion
- Range (R) measures the difference between the maximum and minimum value in a data set
- Standard deviation is a measure of dispersion that uses the amount by which each individual data value deviates from the mean and is less sensitive to extreme values
- Variance for a given set of data is the square of the standard deviation
Percentiles and Quartiles
- Percentiles divide a data distribution into equal groups, with a single value representing the percentage of scores that fall below a certain point
- Quartiles divide a ranked data set into four equal groups, with three specific values (Q1, Q2, Q3) representing the division points
Arguments and Truth Tables
- Arguments can be represented symbolically.
- Each premise is a statement that is accepted as true.
- The conclusion is a statement that is supposed to be true based on the premises.
- A truth table is used to determine the validity of an argument.
- If the conclusion is true in every row of the truth table in which all the premises are true, then the argument is valid.
The Median
- The middle number in an ordered set of data is called the median.
- For an even number of data points, the median is the average of the two middle numbers.
The Mode
- The mode is the data point that appears most often in a set of data.
- A set of data may have no mode or multiple modes if multiple data points appear the same number of times.
The Weighted Mean
- Some data values may be more important than others, requiring weighted means.
- Weights are assigned to each data value, and the sum of each data value multiplied by its weight is divided by the sum of the weights.
Standard Deviation
- Measures the amount of variation or dispersion of a set of data values from their mean.
- A higher standard deviation indicates a greater amount of variation.
Variance
- The square of the standard deviation.
- A larger variance indicates greater variation in the data.
Z-score
- Represents how many standard deviations a data point is away from the mean.
- A z-score of 0 indicates the data point is equal to the mean.
Percentiles
- Indicate the percentage of data points in a set that fall below a certain data value.
- For a data set with n data points, the pth percentile is the value that has p percent of the data points below it.
- For a data set, the percentile rank for a data point x is the percentage of data points in the set that are less than or equal to x.
Quartiles
- The three values that partition a ranked data set into four (approximately) equal groups.
- The second quartile is the median of the data set.
- The first quartile is the median of the data values less than the second quartile.
- The third quartile is the median of the data values greater than the second quartile.
Arguments and Truth Tables
- Arguments can be shown to be valid if they have the same symbolic form as an argument that is known to be valid.
- The three dots ∴ are a symbol for "therefore".
The Median
- Another type of average is the median.
- The median is the middle number or the mean of the two middle numbers in a list of numbers that have been arranged in numerical order from smallest to largest or largest to smallest.
The Arithmetic Mean
- The Arithmetic Mean is a measure of central tendency.
- Statisticians often collect data from small portions of a large group to determine information about the group.
- The entire group under consideration is known as the population, and any subset of the population is called a sample.
- It is traditional to denote the mean of a sample by (which is read as “x bar”) and to denote the mean of a population by the Greek letter (lowercase mu).
- The traditional symbol used to indicate a summation is the Greek letter sigma, .
- The notation x, called summation notation, denotes the sum of all the numbers in a given set.
- The mean can be defined using summation notation.
- The arithmetic mean is the sum of all values divided by the number of values.
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Brush up on your statistical knowledge and see how well you can apply these concepts!