Questions and Answers
What is the value of (d)?
What is the probability that a randomly selected Massachusetts high school basketball player wears Adidas or Reebok sneakers?
What is the probability that you lose the next two matches if you have a probability of 0.6 of winning each match?
If P(A)=0.24 and P(B)=0.52 and A and B are mutually exclusive, what is P(A or B)?
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Which of the following is a valid assignment of digits to represent coffee drinkers in a simulation?
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Two events are said to be mutually exclusive if:
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Which of the following best describes the types of variables that are being measured?
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The overall shape of this distribution is:
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The mean of the distribution (don't try to find it) is:
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Based on the shape of this distribution, what numerical measures would best describe it?
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The number of students whose favorite subject is math is:
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Which of the following is the best interpretation of a z-score of -1.35 for Steve's salary?
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Which of the following are resistant to outliers?
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Which of the distributions below has the larger standard deviation?
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About how many students had scores above 39?
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The median grade is in which of the following intervals?
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This tells us that taller than average fathers tend to have taller than average sons.
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If sons' heights were instead measured in inches, what would happen to the correlation?
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You would draw a segmented bar graph to:
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Does a positive correlation between the number of laptops and average life expectancy indicate causation?
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Which statement must be true about the individual represented by the indicated point in a residual plot?
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The correlation between male and female illiteracy rates is r=0.945. What does this tell us?
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Which variable would you put on the horizontal axis of a scatterplot in a study of TV hours and reading scores?
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If point (20, 25) is removed from a dataset, which statement is TRUE?
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Which statement about the regression line is true?
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What is the purpose of random assignment of treatments to subjects in an experiment?
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A random number generator selects 12 students from a large statistics class. The 12 students selected are:
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The population for this sample survey appears to be:
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This means that we expect that between 51% and 55% of all adult Americans think we should have a third party.
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Describe how nonresponse might lead to bias in this study.
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Describe how response bias might lead to bias in this study.
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What is the probability he will make the next free throw?
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If quizzes are given independently of the day, what is the probability there will be a surprise quiz on the next two consecutive days?
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Which of the following statements is false?
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What is the probability a randomly selected voter is affiliated with some other party?
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What is the probability a randomly selected customer buys 3 raffle tickets?
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Study Notes
General Statistics Concepts
- Variables can be classified as categorical or quantitative; example survey measures age, gender, address duration, favorite subject, and college plans.
- Distribution shapes: left-skewed indicates a longer tail on the left; mean can be less than or greater than the median based on skewness.
- The five-number summary (min, Q1, median, Q3, max) provides insights into data distribution and is useful for box plots.
Measures of Central Tendency & Spread
- Median and Interquartile Range (IQR) are resistant measures of central tendency and spread, not affected by outliers unlike mean and standard deviation.
- Understanding correlation coefficients: r = 0.89 implies a strong positive relationship between two variables, as observed in height data between fathers and sons.
Graphical Representations
- Segmented bar graphs can explore associations between categorical variables, such as gender and favorite childhood toys.
- Scatterplots are effective in visualizing relationships between two continuous variables; least squares regression lines depict best-fit for prediction.
Sampling & Experiments
- Random assignment in experiments aims for equivalent treatment groups, reducing bias.
- Random samples yield unbiased insights about larger populations, while nonresponse can skew results if non-respondents share similar traits.
Statistics in Surveys
- Population in survey context refers to the entire group represented; for instance, the survey of U.S. adults assessing political opinions.
- Margins of error provide a range within which the true population parameter lies, indicating some uncertainty in survey findings.
Probability Concepts
- Probability calculations for independent events, such as quizzes occurring over multiple days, involve multiplying probabilities together.
- Understanding mutual exclusivity is crucial in probability; events cannot occur simultaneously.
Confounding Variables & Bias
- Confounding variables can complicate causal interpretations; for example, night light usage and myopia in children suggest a relationship influenced by genetic factors.
- Response bias occurs when participants' answers reflect perceived expectations rather than true opinions, impacting result validity.
Experimental Design
- Double-blinding in experiments occurs when neither subjects nor experimenters know treatment allocations, minimizing bias in result interpretation.
- Placebo groups are essential to understand treatment effects compared to no treatment, ensuring ethical considerations are met.
Calculating Outcomes
- Familiarity with basic probability models, such as raffle ticket purchasing or sneaker brand popularity, enables clear interpretation of statistical information.
- Conditional probabilities and total probabilities can guide predictions about demographic behaviors, like coffee consumption rates.
Advanced Topics
- Correlation does not imply causation; statistical associations should not be misinterpreted as direct relationships.
- Understanding inference from sample data to make generalizations about populations is a core aspect of statistics, requiring careful consideration of sampling methods and potential biases.
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Description
Prepare for your Statistics final exam with this study guide featuring flashcards. Each card includes important concepts, definitions, and examples that will help reinforce your understanding of variables and data types used in statistical analysis.