A real estate agent believes that the mean home price in the northern part of a county is higher than the mean price in the southern part of the county and would like to test the claim. A simple random sample of housing prices is taken from each region. The results are shown below. Mean Variance Observations Pooled Variance Hypothesized Mean Difference df t Stat P(T<=t) one-tail t Critical one-tail P(T<=t) two-tail t Critical two-tail Confidence Level Southern Northern 155.056 168.889 345.938 560.928 18 18 453.433 0 34 1.949 0.030 2.441 0.060 2.728 99% ↑ T 0 p = Ex: 1.234 1 2 t = Ex: 1.234

The variance in a production process is an importance measure of the quality of the process. A large variance often signals an opprotunity for improvement in the process by finding ways to reduce the process variance. The conduct a statistical test to determine whether there is a significant differeence between the variance in the bag weights for two machines. Use a 0.05 level of significance. What is your conclusion? Which machine, if either, provides the greater opportunity for quality improvements?    Machine 1 Machine 2 2.95 3.22 3.45 3.30 3.50 3.34 3.75 3.28 3.48 3.29 3.26 3.25 3.33 3.30 3.20 3.27 3.16 3.38 3.20 3.34 3.22 3.35 3.38 3.19 3.90 3.35 3.36 3.05 3.25 3.36 3.28 3.28 3.20 3.30 3.22 3.28 2.98 3.30 3.45 3.20 3.70 3.16 3.34 3.33 3.18   3.35   3.12   Please use excel

An engineer designed a valve that will regulate water pressure on an automobile engine. The engineer designed the valve such that it would produce a mean pressure of 5.5 pounds/square inch. It is believed that the valve performs above the specifications. The valve was tested on 24 engines and the mean pressure was 5.7 pounds/square inch with a variance of 0.49. A level of significance of 0.01 will be used. Assume the population distribution is approximately normal. Make the decision to reject or fail to reject the null hypothesis.

Mean = 5.2 Median=3 Mode= 2  Graph what the distribution would look like. Is it normally distributed? If not, how is it skewed and what might cause this type of skew to the distribution?

A researcher wants to measure average cardiovascular health of university students and compare those scores to the average scores in the general population. Assuming that population variance is known, what statistical test is most appropriate for this study?        independent-samples t-test     single-sample t-test     z-test for sample mean     related-samples t-test