10.3

1.

  1. 2.602

  2. -1.729

  3. ±2.179

2.

  1. 1.321

  2. -2.426

  3. ±2.738

3.

  1. t0=47.1-50/10.3/√24=-1.379

  2. dof:24-1=23 -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

4.

  1. t0=42.3-40/4.3/√25=2.674

  2. dof:25-1=24 t0.1=1.318

  3. skip

  4. The researcher will reject the null hypothesis because the test statistic is in the critical region

5.

  1. t0=104.8-100/9.2/√23=2.502

  2. dof:23-1=22 -t0.005=-2.819/t0.005=2.819

  3. skip

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

  5. (99.393,110.207)

11.

Ho: μ=67

H1: μ>67

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

  2. The null hypothesis would be reject because the p-value is less than the level of signifiance. And there’s sufficient evidence that people withdraw more money from a PayEase ATM.

13.

Ho: μ=22

H1: μ>22

  1. Because the sample is random, the sample size 200 is at least 30. So it is reasonable to assume the sampled values are independent.

  2. t0=22.6-22/3.9/√200=2.176, dof:200-1=199 P(t0>2.176)=0.0154, because 0.0154<0.05, it 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.

H0:μ=9.02, H1:μ<9.02 t0=8.10-9.02/0.7/√12=-4.553 -t0.01=-2.718 Because -4.553<-2.718, so it reject the null hypothesis. And there is sufficient evidence to conclude that hippocampal volumes in alcoholic adolescents are less than the normal volume of 9.02 cm3

17.

t0=396.9-355.7/45.4/√12=3.144 t0.05=1.796 Because 3.144>1.796, so it reject the null hypothesis. And there is sufficient evidence to conclude that the kidney weight of mice is greater than 355.7 mg

19.

95% confidence interval (35.439,42.361), the interval includes 40.7, which means that the mean age of a deeath-row inmate has not changed from 2002

10.4

1.

  1. 28.87

  2. 14.04

  3. 16.05, 45.72

3.

  1. X20=(24-1)(47.22)/50^2=20.50

  2. dof:24-1=23, X^20.95=13.09

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

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

X20=(10-1)(15.2)2/182=6.418 X20.95=3.325 Because 6.418>3.325, so it does not reject the null hypothesis. And there is not sufficient evidence to conclude that the standard deviation of the wait time is less than 18 seconds.

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.

X20=(25-1)(6.7)2/8.32=15.64 X20.9=15.66 Because 15.64<16.66, so it reject the null hypothesis. And there is sufficient evidence to conclude that Derrick Rose is more consistent than other shooting guards.