Ch 7 Hypothesis Tests MC Review

Experiments on learning in animals sometimes measure how long it takes mice to find their way through a maze. The mean time is 18 seconds for one particular maze. A researcher thinks that a loud noise will cause the mice to complete the maze faster. She measures how long each of 10 mice takes with a noise stimulus. The appropriate tests for a significance test are:

A mayor is concerned about the percentage of city residents who express disapproval of his job performance.  His political committee pays for a newspaper ad, hoping to keep his disapproval rating below 21%.  They will use a follow up poll to access effectiveness.  What are the correct null and alternative hypotheses?

At the end of the current growing season, the quality inspector took a sample of 50 pineapples and conducted a hypothesis test on the sample data. His test produced a p-value of 0.1317. Based on the p-value, was there convincing evidence that the current pineapples are larger? Use  $\alpha$  =0.05. 

• Since our p-value of 0.1317 is < $\alpha$  , we reject the null hypothesis. We have convincing evidence that the pineapples are larger. 

• Since our p-value of 0.1317 is > $\alpha$  , we fail to reject the null hypothesis. We do not have convincing evidence that the pineapples are larger. 

Suppose the P-value for a hypothesis test is 0.0304. Using a = 0.05, what is the appropriate conclusion?

• a) Reject the null hypothesis

• b) Reject the alternative hypothesis

• c) Fail to reject the null hypothesis

• d) Fail to reject the alternative hypothesis

Last year, a pineapple company in Hawaii grew pineapples that weighed an average of 31 ounces. The company installed a new irrigation system hoping that this year’s crop of pineapples would be larger than 31 ounces.

Write appropriate hypotheses.

• Ho: u = 31 ounces

  Ha: u > 31 ounces

• Ho: u = 31 ounces

  Ha: u < 31 ounces

• Ho: u = 31 ounces

  Ha: u =/= 31 ounces

• Ho: u = 31 ounces

  Ha: u = 31 ounces

A manufacturer has a set limit that the proportion of defective items is not to be over 18%. The buyer thinks the proportions of defective items exceeds the limit. The buyer take a random sample of 90 items and finds that 19 of them are defective.   The z-score is closest to:

• 0.25

• 0.75

• -0.25

• -0.75

Resting pulse rate is an important measure of the fitness of a person's cardiovascular system, with a lower rate indicative of greater fitness. The mean pulse rate for all adult males is approximately 72 beats per minute. A random sample of 25 male students currently enrolled in the Agriculture School at a major university was selected and the mean resting pulse rate was found to be 80 beats per minute with a standard deviation of 20 beats per minute. The experimenter wishes to test if the students are less fit, on average, than the general population. The null and alternative hypotheses are:

• H₀: μ = 72; H_a: μ < 72

• H₀: x-bar = 72; H_a: x-bar < 72

• H₀: μ = 80; H_a: μ =72

• H₀: x-bar = 80; H_a: x-bar > 72

• H₀: μ = 72; H_a: μ > 72

Which of the following represents the appropriate null & alternative hypotheses?

The mean height of women is greater than 64"

• H₀: μ = 64"

  Hₐ: μ > 64"

• H₀: μ < 64"

  Hₐ: μ > 64"

• H₀: p > 64"

  Hₐ: p ≠ 64"

• H₀: p = 64"

  Hₐ: p > 64"

At the Chrysler manufacturing plant, there is a part that is supposed to weigh precisely 19 pounds. The engineers take a sample of parts and want to know if they meet the weight specifications. What are our null and alternative hypotheses?

• H_o : μ = 17, H_a : μ ≠ 19

• H_o : μ = 19, H_a : μ ≠ 19

• H_o : μ = 19, H_a : μ ≠ 17

• H_o : μ = 17, H_a : μ ≠ 17