Questions and Answers
Statistics is used to answer questions with 100% certainty.
False
Determine whether the underlined value is a parameter or a statistic: In a survey conducted in a certain town, 21% of adult respondents reported that they had been involved in at least one car accident in the past ten years.
statistic
Determine whether the underlined value is a parameter or a statistic: A study of 2,000 college students in a certain city found that 5% had been victims of violent crimes.
statistic
Determine whether the underlined value is a parameter or a statistic: 51.9% of the residents of a certain city are female.
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Determine whether the underlined value is a parameter or a statistic: Mark had an average time of 11 seconds for 328 races.
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Identify the sample of interest to university administration: 170 students were followed to determine the average parking time.
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Identify the individuals in a study determining the percentage of cardiologists who had been sued for malpractice.
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Which branch of statistics deals with the organization and summarization of collected information?
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Classify the variable as qualitative or quantitative: the number of calls received at a company's help desk.
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Classify the variable as qualitative or quantitative: the number of seats in a school auditorium.
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Classify the variable as qualitative or quantitative: the numbers on the shirts of a boy's football team.
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Classify the variable as qualitative or quantitative: the weights of cases loaded onto an airport conveyor belt.
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Identify the variables and determine whether each variable is quantitative or qualitative: The table summarizes details of four master's students.
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Quantitative variables classify individuals in a sample according to what?
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Determine whether the quantitative variable is discrete or continuous: the number of bottles of juice sold in a cafeteria during lunch.
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Determine whether the quantitative variable is discrete or continuous: the cholesterol levels of a group of adults.
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Determine whether the quantitative variable is discrete or continuous: the low temperature in degrees Fahrenheit on January 1st in a certain city.
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Determine whether the quantitative variable is discrete or continuous: the number of goals scored in a hockey game.
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Determine whether the quantitative variable is discrete or continuous: the number of phone calls to the police department on any given day.
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Determine whether the quantitative variable is discrete or continuous: the age of the oldest employee in the data processing department.
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Classify the following random variable: telephone area codes.
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A student is asked to rate a guest speaker's ability to communicate as poor, average, good, or excellent. What type of data is being collected?
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Determine the level of measurement of the variable: the medal received (gold, silver, bronze) by an Olympic gymnast.
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Determine the level of measurement of the variable: height of a tree.
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Determine the level of measurement of the variable: the native language of a tourist.
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Determine the level of measurement of the variable: an officer's rank in the military.
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Determine the level of measurement of the variable: weight of rice bought by a customer.
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Determine the level of measurement of the variable: a student's favorite sport.
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Determine the level of measurement of the variable: capacity of a backpack.
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Determine the level of measurement of the variable: the year of manufacture of a car.
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Determine whether the study depicts an observational study or an experiment: A medical researcher obtains a sample of adults suffering from diabetes and assigns them to treatment and placebo groups.
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Determine whether the study depicts an observational study or an experiment: A poll is conducted in which professional musicians are asked their ages.
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Determine whether the study depicts an observational study or an experiment: The personnel director calls each employee to ask about their lunch habits.
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Determine whether the study depicts an observational study or an experiment: A scientist randomizes plots for crop yield study comparing fertilizers.
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Determine whether the study depicts an observational study or an experiment: A researcher compares depression rates among smokers and nonsmokers.
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What procedure would be most appropriate for obtaining a sample of the town's residents for a library survey?
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List all possible simple random samples of size 2 from a committee with 6 members.
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What sampling technique is used when selecting 35 math majors, 26 music majors, and 45 history majors from larger populations?
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Identify the type of sampling used: Every fifth adult entering an airport is checked for extra security screening.
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Identify the type of sampling used: five auto repair classes are randomly selected, and all students from each are interviewed.
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Identify the type of sampling used: all passengers on five randomly selected cruises are interviewed.
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Identify the type of sampling used: a statistics student interviews everyone in his apartment building.
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Identify the type of sampling used: a lobbyist randomly generates numbers to contact senators.
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Identify the type of sampling used: 300 homeowners under and over 65 years old are randomly selected.
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Identify the type of sampling used: the names of 100 employees are randomly drawn from a bag.
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What is the frame for a study of advertising effects on high school boys in small towns?
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The sum of all the relative frequencies of a distribution will always add up to 1.
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What is the difference between a bar chart and a histogram?
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Study Notes
General Concepts of Statistics
- Statistics cannot provide 100% certainty; it deals with uncertainty and variability.
- Parameters describe whole populations, while statistics are derived from samples.
Parameters vs. Statistics
- A percentage from a survey (e.g., 21% of adult respondents involved in accidents) is a statistic.
- Findings from a study of 2,200 college students reporting 5% victims of violent crimes is a statistic.
- A percentage indicating that 51.9% of city residents are female is a parameter.
- An athlete's career average time across races is considered a parameter.
Sampling and Populations
- Sample of interest for parking time includes the times recorded from 170 observed students.
- In studies, individuals are often defined by their population groups, such as cardiologists in a malpractice study.
Types of Statistics
- Descriptive statistics focuses on summarizing and organizing collected data.
Variables Classification
- Variables can be qualitative (e.g., student names, favorite sports) or quantitative (e.g., number of calls, weights).
- Quantitative variables may be discrete (e.g., number of juice bottles sold) or continuous (e.g., cholesterol levels, ages).
Levels of Measurement
- Variables are classified into four levels: nominal (e.g., language), ordinal (e.g., Olympic medals), interval (e.g., year of manufacture), and ratio (e.g., weight of rice).
Study Types
- Experiments involve treatment groups and control groups to assess cause-and-effect relationships.
- Observational studies involve measuring or surveying without intervention to observe existing conditions.
Sampling Techniques
- Random sampling is crucial for eliminating bias, as seen in studies conducted among selected groups or categories.
- Stratified sampling involves dividing the population into subgroups and randomly sampling from each.
- Systematic sampling selects every nth individual in a list, while cluster sampling involves selecting entire groups for study.
Data Collection Methods
- Surveys and interviews are common methods to collect data from specified groups.
- Simple random samples give each individual an equal chance to be selected.
Key Statistical Principles
- The sum of relative frequencies in a distribution should equal 1, considering small rounding errors.
- Bar charts display categorical data while histograms show frequency distributions, with the former's bars not touching and the latter's bars touching.
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Prepare for your Statistics Test with these flashcards covering key concepts and definitions. Each card presents a question related to the fundamentals of statistics, helping you to reinforce your understanding and enhance your knowledge for upcoming exams.
