PSY 315 Week 3 Practice Problem Worksheet

.     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.

 

2.     Using the unit normal table, find the proportion under the standard normal curve that lies to the right of each of the following:

a.     z = 1.00

b.    z = -1.05

c.     z = 0

d.    z = 2.80

e.     z = 1.96

 

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?

b.    Below .10?

c.     Above .20?

d.    Below .20?

e.     Above 1.10?

f.     Below 1.10?

g.    Above -.10?

h.     Below -.10?

 

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.

 

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

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

 

 

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?

b.    Why would that be your best method?