CHECK THE BASICS

For Exercise 22.1, see page 528; for Exercise 22.2, see page 531; and for Exercise 22.3, see page 535.

Question 22.4

22.4 Watching the news. In 2013, the Pew Research Center published a report in which it was claimed that 71% of adults in the United States watch local television news. A researcher believes that significantly fewer than 71% of adults are watching local television news in 2015. To test her theory, she obtains data from a random sample of 1000 adults, and it is observed that 65% of this sample watches local television news. As a first step in conducting a statistical test of significance, the researcher will write a null hypothesis. In this example, the null hypothesis should be what?

  1. (a) H0: p = 0.65

  2. (b) H0: p = 0.71

  3. (c) H0: p > 0.65

  4. (d) H0: p < 0.71

Question 22.5

22.5 College students and the Internet. It is reported that college students spend an average of 100 minutes per day on the Internet. An educational technologist disputes this claim and believes that college students spend more than an average of 100 minutes per day on the Internet. When a random sample of data is obtained and a statistical test of significance is conducted, it is observed that the P-value is 0.01. What is the correct decision to reach based on this P-value?

  1. (a) The data provide strong evidence that the null hypothesis must be true.

  2. (b) The data provide strong evidence that the alternative hypothesis must be true.

  3. (c) The data provide strong evidence against the null hypothesis.

  4. (d) The data provide strong evidence against the alternative hypothesis.

538

Question 22.6

22.6 Statistical significance. If the results of a statistical test are considered to be significant, what does this mean?

  1. (a) The results are important.

  2. (b) The results are not likely to happen just by chance.

  3. (c) The P-value is large.

  4. (d) The alternative hypothesis is true.

Question 22.7

22.7 Pulse rates. Suppose that a report by a leading medical organization claims that the healthy human heart beats an average of 72 times per minute. Advances in science have led some researchers to question if the healthy human heart beats an entirely different amount of time, on average, per minute. They obtain pulse rate data from a sample of 100 healthy adults and find the average number of heart beats per minute to be 75, with a standard deviation of 12. Before conducting a statistical test of significance, this outcome needs to be converted to a standard score, or a test statistic. What would that test statistic be?

  1. (a) 3.0

  2. (b) 2.5

  3. (c) 0.25

  4. (d) 0.03