Exercise 1.

Identify: a. the population, b. the sample, c. the parameter, d. the statistic, e. the variable, and f. the data. Give examples where appropriate.

Political pollsters may be interested in the proportion of people who will vote for a particular cause.

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Exercise 2.

Identify the type of data that would be used to describe a response (quantitative discrete, quantitative continuous, or qualitative), and give an example of the data.

number of competing computer spreadsheet software packages

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Exercise 3.

Data that are not only made up of counting numbers, but that may include fractions, decimals, or irrational numbers, are called

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Exercise 4.

For the following exercises, identify the type of data that would be used to describe a response (quantitative discrete, quantitative continuous, or qualitative), and give an example of the data.

a. time in line to buy groceries.

b. percent of body fat

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Exercise 5.

A study was done to determine the age, number of times per week, and the duration (amount of time) of residents using a local park in San Jose. The first house in the neighborhood around the park was selected randomly and then every eighth house in the neighborhood around the park was interviewed. The sampling method was:

a. simple random

b. systematic

c. stratified

d. cluster

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Exercise 6.

State whether the data are best described as a population or a sample.

To estimate size of trout in a lake, an angler records the weight of12trout he catches over a weekend.

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Exercise 7.

The population is the approximately29,000protein-coding genes in human DNA. Each gene is assigned a number (from1to29,000), and computer software is used to randomly select200of these numbers yielding a sample of200genes.

State whether or not the sampling method described produces a random sample from the given population.

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Exercise 8.

Indicate whether we should trust the results of the following study. Is the method of data collection biased?

Ask a random sample of students at the library on a Friday night "How many hours a week do you study?" to collect data to estimate the average number of hours a week that all college students' study.

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Exercise 9.

We introduce a study by researchers from Harris Interactive who were interested in determining what percent of people wash their hands after using the washroom. They collected data by standing in public restrooms and pretending to comb their hair or put-on make-up as they observed patrons' behavior.¹Public restrooms were observed at Turner's Field in Atlanta, Penn Station and Grand Central Station in New York, the Museum of Science and Industry and the Shedd Aquarium in Chicago, and the Ferry Terminal Farmers Market in San Francisco. Of the over6000people whose behavior was observed,85%washed their hands. Women were more likely to wash their hands:93%of women washed, while only77%of men did. The Museum of Science and Industry in Chicago had the highest hand-washing rate, while men at Turner's Field in Atlanta had the lowest.

Identify each of the following variables as categorical or quantitative:

a.The variable indicating whether or not the person washed their hands.

b.The variable indicating the gender of the individual.

c.The variable indicating the location of the observation.

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Exercise 10.

Is the following an experiment or an observational study?

To examine whether planting trees reduces air pollution, we find a sample of city blocks with similar levels of air pollution and we then plant trees in half of the blocks in the sample. After waiting an appropriate amount of time, we measure air pollution levels.

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