1. Intro to Stats and Collecting Data

In statistics, bivariate data consist of which of the following?

Which of the following best describes the primary purpose of an introductory statistics course?

"Determine whether the statement is true or false. If it is false, rewrite it as a true statement.

For data at the interval level, you cannot calculate meaningful differences between data entries."

Sampling For each of the following, identify the term that best describes the type of sample: systematic, convenience, stratified, cluster, or simple random sample.

a. As Lipitor pills are being manufactured, a quality control plan is to select every 500th pill and test it to confirm that it contains 80 mg of atorvastatin.

Which of the following statements is true about the interquartile range $\mathrm{IQR}$?

Which of the following best describes the difference between a $\mathrm{population}$ and a $\mathrm{sample}$ in statistics?

[DATA] Ramp Metering [See Problem 13 in Section 11.3.] Ramp metering is a traffic engineering idea that requires cars entering a freeway to stop for a certain period of time before joining the traffic flow. The theory is that ramp metering controls the number of cars on the freeway and the number of cars accessing the freeway, resulting in a freer flow of cars, which ultimately results in higher speeds on the road. To test whether ramp metering is effective in reducing travel times, engineers in Minneapolis, Minnesota, conducted an experiment in which a section of freeway had ramp meters installed on the on-ramps. A random sample of 15 cars on the highway for a Monday at 6 P.M. with the ramp meters on and a second random sample of 15 cars on a different Monday at 6 P.M. with the meters off resulted in the following speeds (in miles per hour).

a. What is the explanatory variable in this study? What is the response variable?

Which level of measurement consists of categories only?

Which of the following best describes the difference between a $\mathrm{population}$ and a $\mathrm{sample}$ in statistics?

"Designing an Experiment Researchers want to know if there is a link between hypertension (high blood pressure) and consumption of salt. Past studies have indicated that the consumption of fruits and vegetables offsets the negative impact of salt consumption. It is also known that there is quite a bit of person-to-person variability in the ability of the body to process and eliminate salt. However, no method exists for identifying individuals who have a higher ability to process salt. The U.S. Department of Agriculture recommends that daily intake of salt should not exceed 2400 milligrams (mg). The researchers want to keep the design simple, so they choose to conduct their study using a completely randomized design.

Name three factors that have been identified."

Effects of Clusters Refer to the Minitab-generated scatterplot given in Exercise 10 of Section 10-1.

a. Using the pairs of values for all 8 points, find the equation of the regression line.

Suppose a hospital emergency room records the number of patients arriving each hour over a week. Which type of variable best describes the $number$ of patients arriving per hour?

Quarters. In Exercises 9–12, refer to the accompanying table of weights (grams) of quarters minted by the U.S. government. This table is available in Data Set 44 “Weights of Minted Quarters” in Appendix B.

Quarters: R Chart Treat the five measurements from each day as a sample and construct an R chart. What does the result suggest?

Regression and Predictions

Exercises 13–28 use the same data sets as Exercises 13–28 in Section 10-1.

Find the regression equation, letting the first variable be the predictor (x) variable.

Find the indicated predicted value by following the prediction procedure summarized in Figure 10-5.

Oscars Listed below are ages of recent Oscar winners matched by the years in which the awards were won (from Data Set 21 “Oscar Winner Age” in Appendix B). Find the best predicted age of an Oscar-winning actress given that the Oscar winner for best actor is 59 years of age. How does the result compare to the actual actress age of 60 years?

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Determine the level of measurement of the data set. Explain your reasoning.

The horsepowers of racing car engines