A new cream that advertises that it can reduce wrinkles and improve skin was subject to a recent study. A sample of 68 women over the age of 50 used the new cream for 6 months. Of those 68 women, 39 of them reported skin improvement(as judged by a dermatologist). Is this evidence that the cream will improve the skin of more than 40% of women over the age of 50? Test using  a= 0.05 (a) Test statistic:  z= (b) The final conclusion is... A. There is not sufficient evidence to reject the null hypothesis that p=0.4 . That is, there is not sufficient evidence to reject that the cream can improve the skin of more than 40% of women over 50. B. We can reject the null hypothesis that p=0.4 and accept that p>0.4. That is, the cream can improve the skin of more than 40% of women over 50.

Researchers conducted a study to determine the effects of different types of alcohol on the peak alcohol concentration. In one part of the study, the researchers gave 15 randomly select males a controlled volume of vodka and monitored the subjects' alcohol concentration following the period of consumption. The legal limit for driving is 80 mg/dL (milligrams per deciliter of blood). A hypothesis test was conducted to see if the mean peak alcohol concentration from drinking vodka was different from the legal driving limit. This was reflected in the null and alternative hypotheses ?0:??1:?=80 mg/dL≠80 mg/dL The researchers required their results to be statistically significant at a level of ?=0.10. The mean peak alcohol concentration of the participants after drinking a controlled volume of vodka was 77.4 mg/dL with a standard deviation of 17.25 mg/dL. Determine the confidence interval that corresponds to the ?‑test. Give the lower and upper bounds precise to two decimal places

A study was performed to determine the percentage of people who wear life vests while out on the water. A researcher believed that the percentage was different for those who rode jet skis compared to those who were in boats. Out of 500500 randomly selected people who rode a jet ski, 85%85% wore life vests. Out of 250250 randomly selected boaters, 90.4%90.4% wore life vests. Using a 0.050.05 level of significance, test the claim that the proportion of people who wear life vests while riding a jet ski is not the same as the proportion of people who wear life vests while riding in a boat. Let jet skiers be Population 1 and let boaters be Population 2.   Step 1 of 3 :   State the null and alternative hypotheses for the test. Fill in the blank below. H0Ha: p1=p2: p1⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯p2     Step 2 of 3 :   Compute the value of the test statistic. Round your answer to two decimal places. 3) draw a conclusion and form a decision (word it like "we fail to reject the null hypothesis and…

Reports show that 92% of online searches in March 2021 use Google as the search engine. A network administrator wants to determine whether the percentage of searches that use Google is different in their company. They sample 800 searches and find that 758 of them use Google. Can they conclude that the percentage of searches that use Google in this company differs from 92%? Use the a = 0.05 level of significance.