10.2

7.

  1. 2.315
  2. .0104
  3. Reject the null hypothesis

9.

  1. -.74
  2. .2296
  3. Don’t reject the null hypothesis

11.

  1. -1.49
  2. .1362
  3. Don’t reject the null hypothesis

13.

27.43% of samples will have a sample proportion greater than or equal to the sample proportion where the population proportion is 50%. There is not enough evidence to reject the null hypothesis, so it cannot be concluded that throwing darts is a successful stock-picking strategy.

15.

  1. Z = -1.56, P-value = .9406

  2. .9406 > .05, so the null hypothesis cannot be rejected. There is not enough evidence to assert that his predictions are accurate less than 50% of the time.

17.

  1. Z = .65, P-value = .2578

  2. Since .2578 > .01, the null hypothesis cannot be rejected. There is not sufficient evidence to assert that more than 1.9% of people who take the drug experience flu-like symptoms.

19.

  1. Z = 2.77, P-value = .0028

  2. Since .0028 < .05, the null hypothesis can be rejected. There is sufficient evidence to assert that Hawaii has a higher proportion than the rest of the U.S.

10.3

1.

  1. 2.602

  2. -1.729

  3. +-2.179

2.

  1. 2.508

  2. -2.426

  3. +-2.738

3.

  1. -1.38

  2. -1.714

  3. skip

  4. No, because the fact that -1.38 is greater than the critical value of -1.74 indicates that there’s insufficient evidence to do so.

4.

  1. .267

  2. 1.318

  3. skip

  4. No; the fact that .267 is less than the critical value of 1.318 indicates that there’s insufficient evidence to do so.

5.

  1. 2.5

  2. +-2.819

  3. skip

  4. No, because the test statistic 2.5 is between -2.819 and 2.819.

  5. 100 falls within the confidence interval (99.4,110.2), so there’s (still) insufficient evidence to reject the null hypothesis.

11.

Ho: u = 67

H1: u > 67

  1. For a population with a $67 mean, there’s a 2% probability of selecting a sample with a (sample) mean of $73 or more.

  2. Since the p-value .02 is less than the level of significance .05, there is not sufficient evidence to reject the null hypthesis, suggesting that people withdraw more from a PayEase ATM.

13.

Ho: u = 22

H1: u > 22

  1. Sample was randomly selected. Sample size (200) is greater than 30.

  2. t = 2.176, critical value = 1.66 Since the test statistic 2.176 is greater than the critical value 1.66, there is sufficient evidence to reject the null hypothesis.

  3. There’s sufficient evidence to conclude that students who complete the core curriculum are ready for college-level math (i.e. they score >22 on math).

15.

Since the test statistic -4.55 is less than the critical value -2.718, there is sufficient evidence to reject the null hypothesis, suggesting that the hippocampal volumes in alcoholic adolescents are less than normal.

17.

Since the test statistic .0532 is less than the critical value 1.685, there is not sufficient evidence to reject the null hypothesis, suggesting that high income individuals do not have higher credit scores.

19.

Since the mean 40.7 falls within the 95% confidence interval of (35.4, 42.4), there is not sufficient evidence to reject the null hypothesis, suggesting that mean average age of death row inmates has not changed since 2001.