# data on Taxes

Consider the file data on Taxes that is included in worksheet P2 on the exam template. This data represents property taxes paid by 170 residents that live in a small town. Assume this file to be the entire population. Answer all of the following questions :

a. Conduct a test at the alpha = .05 level to determine if there is a difference in taxes paid by another jurisdiction. The information on this other jurisdiction is population information. In this other jurisdiction, the mean taxes paid by 243 residents are \$1751.68 with a population standard deviation of \$141.62. State Ho and Ha, Critical T or Z, and the decision.

b. What is the 95% confidence interval for the difference between the taxes paid in the two jurisdictions from problem a. State the upper and lower limits.

c. Conduct a test at the alpha = .05 level to determine if there is a difference between taxes paid in neighborhood 1 and in neighborhood 4. Use all the data points from both neighborhoods and consider this to be sample data. State Ho and Ha, Critical T or Z, Calculated T or Z, and the decision.

d. From part c, what is the 95% confidence interval for the difference between means in the two neighborhoods. State the upper and lower limits.

e. For part c, conduct a test at alpha = .05 to see if the variances between the two neighborhoods are unequal. State F Critical, F Test, and the decision.

Problem #2

An engineering statistician wants to conduct a test to determine if there is a difference in the compression strength of two different manufactures of reinforced concrete columns. Each manufacturer has provided sample data for compression strength (column failure) as follows:

Manufacturer 1: mean compression strength is 956 KSI based on 30 samples with a standard deviation of 192 KSI.

Manufacturer 2: mean compression strength of 898 KSI based on 25 samples with a standard deviation of 256 KSI

Conduct a test at alpha equal to .01 to see if there is a difference between the two different manufacturers. Consider the data to be from two different populations. State Ho and Ha, Critical T or Z, Calculated T or Z, p Value, and the decision.

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