A professor is concerned that the two sections of college algebra that he teaches are not performing at the same level. To test his claim, he looks at the mean exam score for a random sample of students from each of his classes. In Class 1, the mean exam score for 12 students is 80.8 with a standard deviation of 5.7. In Class 2, the mean exam score for 14 students is 84.5 with a standard deviation of 4.9. Test the professor's claim at the 0.01 level of significance. Assume that both populations are approximately normal and that the population variances are equal. Let Class 1 be Population 1 and let Class 2 be Population 2. Step 1 of 3: State the null and alternative hypotheses for the test. Fill in the blank below. Ho: M₁ = 4₂ Ha: M M₂

The manager of a major retail store has taken a random sample of 25 customers. The average sale was $52.50. The population standard deviation is known to be $6.10. The manager would like to determine whether or not the mean sales by all customers are significantly more than $50. What is the p-value for the test?

Lucy recently switched her primary doctor to one specializing in caring for elderly patients. On her new doctor's website, it says that the mean systolic blood pressure among elderly females is 120 millimeters of mercury (mmHg). Lucy believes the value is actually higher. She bases her belief on a recently reported study of 19 randomly selected, elderly females. The sample mean systolic blood pressure was 132 mmHg, and the sample standard deviation was 24 mmHg. Assume that the systolic blood pressures of elderly females are approximately normally distributed. Based on the study, at the 0.05 level of significance, can it be concluded that μ, the population mean systolic blood pressure among elderly females, is greater than 120 mmHg? Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places. (If necessary, consult a list of formulas.) esc (a) State the null hypothesis H and the alternative hypothesis H₁. Ho: H₁:0 (b)…

Ann recently switched her primary doctor to one specializing in caring for elderly patients. On her new doctor's website, it says that the mean systolic blood pressure among elderly females is 120 millimeters of mercury ( mmHg ). Ann believes the value is actually higher. She bases her belief on a recently reported study of 10 randomly selected, elderly females. The sample mean systolic blood pressure was 128 mmHg , and the sample standard deviation was 25 mmHg . Assume that the systolic blood pressures of elderly females are approximately normally distributed. Based on the study, at the 0.10 level of significance, can it be concluded that μ , the population mean systolic blood pressure among elderly females, is greater than 120 mmHg ?   Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places. (If necessary, consult a list of formulas.) (a) State the null hypothesis H0 and the…

An instructor claims that the average number of hours needed to study for a final exam in order to pass should be 5 hours. A student believes that the instructor is understating the number of hours needed to pass and surveys 36 students and finds the sample mean and standard deviation to be 5.7  and 1.5 hours respectively.  Test the instructors claim at a .10 level.

Use z scores to compare the given values. The tallest living man at one time had a height of 238 cm. The shortest living man at that time had a height of 142.4 cm. Heights of men at that time had a mean of 175.45 cm and a standard deviation of 5.59 cm. Which of these two men had the height that was more extreme? ... Since the z score for the tallest man is z = 0 and the z score for the shortest man is z = the man had the height that was Im- more extreme. (Round to two decimal places.) shortest tallest

Heather recently switched her primary doctor to one specializing in caring for elderly patients. On her new doctor's website, it says that the mean systolic blood pressure among elderly females is 115 millimeters of mercury (mmHg). Heather believes the value is actually higher. She bases her belief on a recently reported study of 13 randomly selected, elderly females. The sample mean systolic blood pressure was 125 mmHg, and the sample standard deviation was 25 mmHg. C Assume that the systolic blood pressures of elderly females are approximately normally distributed. Based on the study, at the 0.05 level of significance, can it be concluded that u, the population mean systolic blood pressure among elderly females, is greater than 115 mmHg? Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places. (If necessary, consult a list of formulas.) (a) state the null hypothesis Ho and the alternative hypothesis H₁. 1 H₂ : 0…

Amanda recently switched her primary doctor to one specializing in caring for elderly patients. On her new doctor's website, it says that the mean systolic blood pressure among elderly females is 115 millimeters of mercury (mmHg). Amanda believes the value is actually higher. She bases her belief on a recently reported study of 17 randomly selected, elderly females. The sample mean systolic blood pressure was 123 mmHg, and the sample standard deviation was 23 mmHg. Assume that the systolic blood pressures of elderly females are approximately normally distributed. Based on the study, at the 0.05 level of significance, can it be concluded that μ, the population mean systolic blood pressure among elderly females, is greater than 115 mmHg? Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places.  A. Find the value of the test statistic and round to 3 or more decimal places. (I have posted a picture of an example problem…

Jeff is doing an experiment involving mice. The mice weights have mean weight 2.37 ounces and standard deviation 0.053 ounces. Jeff selects 9 mice independently and calculates the sample mean, x̄, of their weights. What is the standard deviation of x̄?

A newspaper article reports that the mean cost for preventative dental care per year is $175 with a standard deviation of $35 (assume that this is the population standard deviation). You want to test whether the mean cost for preventative dental care in your company is different from what was reported in the article. You take a random sample of 250 employees and find the mean cost is $171. Does this signficantly differ from what was reported in the article? Run the appropriate test at α=0.05. Give each of the following to receive full credit: 1) the appropriate null and alternative hypotheses; 2) the appropriate test; 3) the decision rule; 4) the calculation of the test statistic; and 5) your conclusion including a comparison to alpha or the critical value. You MUST show your work to receive full credit. Partial credit is available.