# 1.On a standard measure of hearing ability, the mean is 300, and the standard

1.On a standard measure of hearing ability, the mean is 300, and the standard deviation is 20. Provide the Z scores for persons whose raw scores are 340, 310, and 260. Provide the raw scores for persons whose Z scores on this test are 2.4, 1.5, and -4.5.

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2.Using the unit normal table, find the proportion under the standard normal curve that lies in the tail for each of the following:

a.z = 1.00 has a proportion of 0.1587

b.z = -1.05 has a proportion of 0.1469

c.z = 0 has a proportion of 0.5

d.z = 2.80 has a proportion of 0.0026

e.z = 1.96 has a proportion of 0.0250

3.Suppose the scores of architects on a particular creativity test are normally distributed. Using a normal curve table (pp. 477–480 of the text), what percentage of architects have Z scores

a.above .10? goes to .4602 or 46.02%

b.below .10?  at 0.5398 or 53.98%

c.above .20? at 0.4207 or 42.07%

d.below .20? at 0.5793 or 57.93%

e.above 1.10? at 0.1357 or 13.57%

f.below 1.10? at 0.8643 or 86.43%

g.above -.10? at 0.5398 or 53.98%

h.below -.10? at .4602 or 46.02%

4.A statistics instructor wants to measure the effectiveness of his teaching skills in a class of 102 students (N = 102). He selects students by waiting at the door to the classroom prior to his lecture and pulling aside every third student to give him or her a questionnaire.

a.a. Is this sample design an example of random sampling? Explain.

b.Assuming that all students attend his class that day, how many students will the instructor select to complete his questionnaire?

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5.Suppose you were going to conduct a survey of visitors to your campus. You want the survey to be as representative as possible.a.How would you select the people to survey?

Making some assumptions (that there is a register for visitor for example):  I would use the list of upcoming visitors throughout the year, I would then assign a number to each individual on this list and use an automatic randomizer to select those who would receive a questionnaire.

b.Why would that be your best method?