In a previous study conducted several years ago, a man owned on average 14 dress shirts. The standard deviation of the population is 3. A researcher wishes to see if that average has changed. He selected a random sample of 45 men and found that the average number of dress shirts that they owned was 13.8. At α=0.05, is there enough evidence to support the claim that the average has changed? Assume that the variable is normally distributed. Use the P-value method with tables. The hypothesis is a two-tailed test.  Compute the test value. Always round z score values to at least two decimal places. Thank You!!

Agricultural scientists are testing a new chicken feed to see whether it increases the number of eggs laid. The scientists divided a flock in half and gave half of the chickens the new feed, while the other half were given a regular feed. The eggs laid in a one-year period for a random sample of 10 chickens using the new feed and 10 chickens using the regular feed are recorded. Assume that the population standard deviation of number of eggs laid is 12 eggs per year for both groups and that the number of eggs laid per year is normally distributed. Let the chickens given the new feed be the first sample, and let the chickens given the regular feed be the second sample. The scientists conduct a two-mean hypothesis test at the 0.05 level of significance to test if there is evidence that the new feed increases the number of eggs laid.   (a)  Which answer choice shows the correct null and alternative hypotheses for this test? Select the correct answer below:   H0:μ1=μ2;…

Let x be a random variable that represents the pH of arterial plasma (l.e., acidity of the blood). For healthy adults, the mean of the x distribution is = 7.4.t A new drug for arthritis has been developed. However, it is thought that this drug may change blood pH. A random sample of 31 patients with arthritis took the drug for 3 months. Blood tests showed that x = 8.8 with sample standard deviations = 3.3. Use a 5% level of significance to test the claim that the drug has changed (either way) the mean pH level of the blood. A USE SALT (a) What is the level of significance? State the null and alternate hypotheses. O Hg: u + 7.4; H,: = 7.4 O Hg: H = 7.4; H,: H > 7.4 O H,: H = 7.4; H,i 7.4; H,: H = 7.4 O H: = 7.4; H,: H# 7.4 (b) What sampling distribution will you use? Explain the rationale for your choice of sampling distribution. O The Student's t, since the sample size is large a is known. O The standard normal, since the sample size is large and a is known. O The standard normal,…

Last year, the standard deviation of the ages at UTM was 1.8 years. Recently, a sample of 61 students had a standard deviation of 2.1 years. We are interested in testing to see if there has been a significant increase in the standard deviation of the ages of the students at UTM. Assume ages are Normally distributed. The p-value for this test is

In a random sample of 8 cell phones, the mean full retail price was $549.30 and the standard deviation was $182.00. Further research suggests that the population mean is $425.14. Does the t-value for the original sample fall between - to 95 and to 95? Assume that the population of full retail prices for cell phones is normally distributed. The t-value of t = fall between - to 95 and to 95 because to 95 (Round to two decima d.) does not does

A hiring company claims that the variance of the annual salaries for managers is greater in Florida than Georgia. You select a sample of 28 managers in Florida and find the standard deviation to be $11,000. You select a sample of 24 managers in Georgia and find the standard deviation to be $9,200. At α=0.05, can you support the hiring company's claim?

It takes an average of 14 minutes for blood to begin clotting after an injury.  An EMT wants to see if the average will change if the patient is immediately told the truth about the injury. The EMT randomly selected 43 injured patients to immediately tell the truth about the injury and noticed that they averaged 12.5 minutes for their blood to begin clotting after their injury. Their standard deviation was 3.1 minutes. What can be concluded at the the αα = 0.01 level of significance? For this study, we should use     The null and alternative hypotheses would be:       H0:H0:                   H1:H1:               The test statistic     =  (please show your answer to 3 decimal places.) The p-value =  (Please show your answer to 4 decimal places.) The p-value is     αα Based on this, we should      the null hypothesis. Thus, the final conclusion is that ... The data suggest the population mean is not significantly different from 14 at αα = 0.01, so there is statistically significant…

Newspaper Reading Times A survey taken several years ago found that the average time a person spent reading the local daily newspaper was 10.8 minutes. The standard deviation of the population was 3  minutes. To see whether the average time had changed since the newspaper's format was revised, the newspaper editor surveyed 40  individuals. The average time that the 40  people spent reading the paper was 12.4  minutes. At α=0.10 , is there a change in the average time an individual spends reading the newspaper? Find the 90%  confidence interval of the mean. **NOTE** I already have answer for a,b, and c    (d)Make the decision.   ▼(Choose one) the null hypothesis.       (e)Summarize the results.   There ▼(Choose one) enough evidence to support the claim that there is a change in the average time an individual spends reading the newspaper. Find the 90% confidence interval of the mean. Round the answers to nearest whole number. <u<   (f)Do the results agree?…