10.3

1.

  1. 2.602

  2. -1.729

  3. +-2.179

3.

  1. t = -1.379

  2. With 24-1 = 23 degrees of freedom, the critical value is -t0.05 = -1.714

  3. skip

  4. The researcher will not reject the null hypothesis because the test statistic is not in the critical region.

5.

  1. t = 2.502

  2. With 23 - 1= 22 degrees of freedom, the critical values are -t = -2.819 and t = 2.819

  3. skip

  4. The researcher will not reject the null hypothesis because the test statistic is not in the critical region.

  5. Using technology, the 99% confidence intercal is (99.393,110.207)

11.

Ho: mew = $67

H1: mew > $67

  1. The p value of 0.02 means that if the null hypothesis is true, this type of result would be expected in about 2 out of 100 samples.

  2. Reject the null hypothesis because the p value is less than the level of significance.

13.

Ho: mew = 22

H1: mew > 22

  1. It is given that the sample is random. The sample size, 200, is at least 30. It is reasonable to assue the sampled values are independent.

  2. Classical approach: the critical value is t = 2.653. Since 2.176 > 1.653, reject the null hypothesis

  3. There is sufficient evidence to conclude that students who complete the core curriculum are ready for college level mathematics.

15.

p value: P(t < -4.553) = 0.0004 Since -4.553 < -2.718 and 0.0004 < 0.01, reject the null hyptohesis.

17.

p value: P(t< -4.553) = 0.0004 Since -4.553

19.

95% confidence interval: 35.439-42.361 Mean age has not changed.

10.4

1.

  1. 28.869.

  2. 14.041.

  3. 16.047-45.722.

3.

  1. 20.496.

  2. critical value = 24.769.

  3. Skip but feel free to sketch on a piece of paper for your benefit.

  4. Don’t reject null hypothesis. Statistic not in critical region.

13. Feel free to use any method you want. If you use the classical method please report the value of your test statistic and your decision. Likewise if you use the pvalue method please state your pvalue and your decision. Hint: The sample standard deviation (s) is 15.20.

pvalue = 0.3025 Do not reject the null hypothesis.

15. Feel free to use any method you want. If you use the classical method please report the value of the test statistic and your decision. Likewise if you use the pvalue method please state your pvalue and your decision.

pvalue = 0.0993 Reject the null hypothesis.