1.
t0.01 = 2.602.
-t0.05 = -1.729.
±t0.025 = ±2.179.
2.
Critical value: 1.321.
Critical value: -2.426.
Critical value: ±2.738.
3.
t0 = -1.379.
-t0.05 = -1.714.
Skip this problem.
No enough evidence for the researcher to reject the null hypothesis because it is a left-tailed test and the test statistic is greater than the critical value (-1.379 > -1.714).
4.
Test statistic = 2.67.
Critical values = 1.318.
Skip this problem.
We reject the null hypothesis because the test statistic is greater than the critical value (2.67>1.318) in a right tailed test.
5.
t0 = 2.502.
-t0.05 = -2.819;t0.05 = 2.819.
Skip this problem.
No enough evidence for the researcher to reject the null hypothesis, since the test statistic is between the critical values (-2.819 < 2.502 < 2.819).
Lower bound: 99.39, Upper bound: 110.21. We do not reject the statement in the null hypothesis because the 99% confidence interval includes 100.
11.
Ho: μ = $67.
Ha: μ > $67.
There is a 0.02 probability of obtaining a sample mean of $73 or higher from a population whos mean is $67. So, if we ontained 100 simple random samples of size n = 40 from a population those mean is $67, we would expect about 2 of these samples to result in sample means of $73 or higher.
Because the P-value is low (P-value = 0.02 < a = 0.05) 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 There is sufficient evidence to conclude that the mean dollar amount withdrawn from a PayEase ATM is more than the mean amount from a standard ATM (more than $65).
13.
Ho: μ = 22.
Ha: μ > 22.
The sample is random. The sample size is large, n = 200 > 30. We can assume that the sample is small reltive to the population, so the scores are independent.
Classical approach: t0 = 2.176 > t0.05 = 1.660; reject the null hypothesis.
Enough evidence to conclude that students who complete the core curriculum are scoring above 22 on the math portion of the ACT.
15.
Test Statistic = -4.553.
Reject the null hypothesis because there is sufficient evidence to conclude that the mean hippocampal volume in alcoholic adolescents is less than the normal mean volume of 9.02 cm^3.
17.
Test Statistic = 0.813.
Do not reject the null hypothesis because there is not sufficient evidence to conclude that the mean FICO score of high-income individuals is greater than that of the general population. Meaning, it is not unlikely to obtain a mena credit score of 714.2 or higher even though the true population mean credit score is 703.5.
19.
95% confidence interval: Lower Bound: 35.44 years, Upper Bound: 42.36 years.
Due to the interval including 40.7 years, there is not enough evidence to conclude that the mean age of death row inmate has changed since 2002.
1.
Critical Value = 28.869.
Critical Value = 14.041.
Critical Values =16.047;45.722.
3.
Test Statistic = 20.496.
Critical Value = 13.091.
Skip this problem
Do not reject the null hypothesis because test statistic > critical value.
13.
Note. The sample standard deviation of the data shown is.\(15.205043\). You will have to knit this to see the number though.
Test Statistic = 6.422.
Do not reject the null hypothesis at the a = 0.05 level of significance. There is not sufficient evidence at the a = 0.05 level of significance to conclude that the standard deviation wait-time is less than 18.0 seconds.
15.
Test Statistic = 15.639.
Reject the null hypothesis at the a = 0.10 level of significance. There is sufficient evidence at the a = 0.10 level of significance to conclude that Rose is a more consistent plater than other shooting guards in the NBA.