3. A national newspaper writes an article that claims the average American gets their first tattoo at 24 years old. A local tattoo parlor thinks the mean in the area is less than that. A random sample of 24 people with tattoos gives a mean age of 22.5 for their first tattoo with a standard deviation of 4.5. Assume age of first tattoo is normally distributed. Conduct a hypothesis test with significance level 0.05 to test the tattoo parlor's claim. (Make sure to include everything for a hypothesis test. You may use either method to determine whether to reject the null hypothesis.)

Fran is training for her first marathon, and she wants to know if there is a significant difference between the mean number of miles run each week by group runners and individual runners who are training for marathons. She interviews 42 randomly selected people who train in groups and finds that they run a mean of 47.1 miles per week. Assume that the population standard deviation for group runners is known to be 4.4 miles per week. She also interviews a random sample of 47 people who train on their own and finds that they run a mean of 48.5 miles per week. Assume that the population standard deviation for people who run by themselves is 1.8 miles per week. Test the claim at the 0.01 level of significance. Let group runners training for marathons be Population 1 and let individual runners training for marathons be Population 2.   Step 2 of 3 :   Compute the value of the test statistic. Round your answer to two decimal places.

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…