# Statistics

## Warm-up

### A study of 2958 collegiate soccer players showed that 46 players suffered ACL tears. Of these 46 players, 36 were women.

   What percent of players who experienced tears are women? are men?

Can it be concluded that women soccer players tear their ACL more often than men?

How might this study’s conclusion been reached?

## Warm-up

### Why are control groups needed in experiments?

Identify the population: A survey of 500 adults in the U.S. found that 54% drink coffee daily.

A. Collection of the 500 adults surveyed B. Collection of all adults in the U.S.

C. 54% D. 500

Identify the population: A survey of 500 adults in the U.S. found that 54% drink coffee daily.

A. Collection of the 500 adults surveyed B. Collection of all adults in the U.S.

C. 54% D. 500

Identify the sample: A survey of 500 adults in the U.S. found that 54% drink coffee daily.

A. Collection of the 500 adults surveyed B. Collection of all adults in the U.S.

C. 54% D. 500

Identify the sample: A survey of 500 adults in the U.S. found that 54% drink coffee daily.

A. Collection of the 500 adults surveyed B. Collection of all adults in the U.S.

C. 54% D. 500

True or false: In the statement “A survey of 500 adults in the U.S. found that 54% drink coffee daily” 54% is a parameter.

A.True

B. False

True or false: In the statement “A survey of 500 adults in the U.S. found that 54% drink coffee daily” 54% is a parameter.

A.True

B. False

True or false: The costs of items in a shopper’s grocery cart represent quantitative data.

A. True B. False

True or false: The costs of items in a shopper’s grocery cart represent quantitative data.

A. True B. False

True or false: The social security numbers of students in a class represent quantitative data.

A. True B. False

True or false: The social security numbers of students in a class represent quantitative data.

A. True B. False

Identify the data set’s level of measurement: The IQ scores of students in a class.

A. Nominal B. Ordinal C. Interval D. Ratio

Identify the data set’s level of measurement: The IQ scores of students in a class.

A. Nominal B. Ordinal C. Interval D. Ratio

Identify the data set’s level of measurement: The nationality of each person on an airplane.

A. Nominal B. Ordinal C. Interval D. Ratio

Identify the data set’s level of measurement: The nationality of each person on an airplane.

A. Nominal B. Ordinal C. Interval D. Ratio

Identify the data set’s level of measurement: The salaries of nurses at a hospital.

A. Nominal B. Ordinal C. Interval D. Ratio

Identify the data set’s level of measurement: The salaries of nurses at a hospital.

A. Nominal B. Ordinal C. Interval D. Ratio

Decide which method of data collection would be most appropriate: A study of the effect of using MyStatLab on grades in a statistics course.

A. Observational study B. Experiment C. Simulation D. Survey

Decide which method of data collection would be most appropriate: A study of the effect of using MyStatLab on grades in a statistics course.

A. Observational study B. Experiment C. Simulation D. Survey

Identify the sampling technique used: Students are classified according to major. Twenty students are selected from each major and asked how often they use the library.

A. Random sample B. Stratified sample C. Cluster sample D. Systematic sample

Identify the sampling technique used: Students are classified according to major. Twenty students are selected from each major and asked how often they use the library.

A. Random sample B. Stratified sample C. Cluster sample D. Systematic sample

A survey of 200 adults in the U.S. found that 76% regularly wear seatbelts while driving.

True or false: 76% is a parameter.

A. True B. False

A survey of 200 adults in the U.S. found that 76% regularly wear seatbelts while driving.

True or false: 76% is a parameter.

A. True B. False

True or false: The checking account numbers of customers at a bank represent quantitative data.

A. True B. False

True or false: The checking account numbers of customers at a bank represent quantitative data.

A. True B. False

Determine whether the quantitative variable is continuous or discrete.

The time (in minutes) required for a student to complete a quiz.

A. Continuous B. Discrete

Determine whether the quantitative variable is continuous or discrete.

The time (in minutes) required for a student to complete a quiz.

A. Continuous B. Discrete

Identify the variable’s level of measurement: Consumer Reports’ ratings (Best Buy, Recommended, Not Recommended).

A. Nominal B. Ordinal C. Interval D. Ratio

Identify the variable’s level of measurement: Consumer Reports’ ratings (Best Buy, Recommended, Not Recommended).

A. Nominal B. Ordinal C. Interval D. Ratio

Determine whether the study depicts an observational study or an experiment: Two sections of statistics are taught by the same teacher. One section uses MyStatLab; the other section does not. At the end of the semester grades in the two sections are compared.

A. Observational study B. Experiment

Determine whether the study depicts an observational study or an experiment: Two sections of statistics are taught by the same teacher. One section uses MyStatLab; the other section does not. At the end of the semester grades in the two sections are compared.

A. Observational study B. Experiment

Identify the type of sampling used: Students at a university are classified according to major. The administration randomly selects five majors. All students majoring in those five areas are surveyed.

A. Simple random sample B. Stratified sample C. Cluster sample D. Systematic sample

Identify the type of sampling used: Students at a university are classified according to major. The administration randomly selects five majors. All students majoring in those five areas are surveyed.

A. Simple random sample B. Stratified sample C. Cluster sample D. Systematic sample

Determine the type of sampling bias: A college wants to survey students about reducing the hours of the computer lab. To conduct the survey, they select the next 50 students to enter the computer lab.

A. Sampling bias B. Response bias C. Nonresponse bias

Determine the type of sampling bias: A college wants to survey students about reducing the hours of the computer lab. To conduct the survey, they select the next 50 students to enter the computer lab.

A. Sampling bias B. Response bias C. Nonresponse bias

Determine the type of experimental design: A company wants to study the relationship between product placement on a shelf and sales volume. Twenty stores of comparable size are selected and 5 stores are randomly assigned to each of the 4 shelf levels. After a month, the sales volumes of each group are compared.

A. Matched Pair B. Completely Randomized Design C. Randomized Block Design

Determine the type of experimental design: A company wants to study the relationship between product placement on a shelf and sales volume. Twenty stores of comparable size are selected and 5 stores are randomly assigned to each of the 4 shelf levels. After a month, the sales volumes of each group are compared.

A. Matched Pair B. Completely Randomized Design C. Randomized Block Design

## Caffeine and Health Risks

  In the 1980’s, a study linked coffee to a higher risk of heart disease and pancreatic cancer. In the early1990’s, studies showed that drinking coffee posed a minimal health risk. However, in 1994, a study showed that pregnant women who drank 3 or more cups of tea may be at risk for spontaneaous abortion. In 1998, a study claimed that women who drank more than a half-cup of caffeinated tea every day may actually increase fertility. In 1998, a study showed over that over a lifetime, a few extra cups of coffee a day can raise blood pressure, heart rate, and stress. More recently some studies have indicated that green tea can reduce the risk of heart disease and cancer.

Suggest some reasons why these studies appear to be conflicting.