10.3

1.

  1. 2.602

  2. -1.729

  3. +-2.179

2.

  1. 1.321

  2. -2.426

  3. +-2.738

3.

  1. -1.379

  2. -1.714

  3. Skip this problem.

  4. will not reject the null hypothesis

4.

  1. 2.674

  2. 1.318

  3. Skip this problem.

  4. will reject the null hypothesis

5.

  1. 2.502

  2. +-2.819

  3. Skip this problem.

  4. will not reject the null hypothesis

  5. (99.39, 110.21) reject the null hypothesis

11.

Ho: μ=67

Ha: μ>67

  1. A P-value of 0.02 means that there is a 0.02 probability of obtaining a sample mean of $73 or higher from a population whose mean is $67. If we obtained 100 simple random samples of size n = 40 from a population whose mean is $67, about 2 of these samples to result in sample means of $73 or higher.

  2. we reject the statement in the null hypothesis.There is sufficient evidence to conclude that the mean dollar amount withdrawn from a PayEase ATM is more than the mean amount from a standard ATM. That is, the mean dollar amount withdrawn from a PayEase A TM is more than $67.

13.

H0 : μ = 22

Ha: μ > 22

  1. The sample is random,and the sample size is large: n > 30. We can reasonable assume that the sample is small relative to the population, so the observations are independent. The assumptions to conduct the t-test appear to be satisfied.

  2. Because this is a right-tailed test with 199 degrees of freedom, the critical value is t0.05 =1.660. Since > t0.05 = 1.660 , the test statistic falls inside the critical region. We reject the null hypothesis.

  3. There is sufficient evidence to conclude that the mean ACT score is greater than 22 for the students who complete the core curriculum.

15.

Since P-value < α = 0.01 , we reject the null hypothesis.

There is sufficient evidence to conclude that the mean hippocampal volume in alcoholic adolescents is less than the normal volume of 9.02

17.

Since t0 = 0.813 < t0.05 = 1.685 , the test statistic does not fall within the critical region. We do not reject the null hypothesis.

There is not sufficient evidence to conclude that the mean FICO score of high- income individuals is greater than that of the general population. In other words, it is not unlikely to obtain a mean credit score of 714.2 even though the true population mean credit score is 703.4.

19.

(35.44, 42.36)

Because this interval includes the hypothesized mean 40.7 years, we do not reject the null hypothesis. Thus, there is not sufficient evidence to conclude that the mean age of death-row inmates has change since 2002.

10.4

1.

  1. 28.869

  2. 14.041

  3. 16.047; 45.722

3.

  1. 20.496

  2. 13.091

  3. Skip this problem

  4. No, will not reject the null hypothesis

13.

Note. The sample standard deviation of the data shown is.\(15.205043\). You will have to knit this to see the number though.

0.303

There is not sufficient evidence to conclude that the standard deviation of weight times is less than 18.0.

15.

15.639

There is sufficient evidence to conclude that Allen Iverson is more consistent than other shooting guards in the NBA