For each of the following examples, indicate whether it is a population or a sample.

All 60 residents in an apartment building responded to a survey regarding the rules and regulations of the building.

Sample. Population

Peyton was interested in churchgoers' level of religiosity. To do this, he surveyed 100 churchgoers in his city about their level of religiosity.

Sample Population

Tina examined how rats responded to a particular drug by injecting 36 rats with the drug and then observed how their bodies reacted.

Sample Population

2. Suppose four of your friends visited a casino over break and their winnings (indicated as positive values) and losses (indicated as negative values) in dollars are as follows:

X

Friend #1 -20

Friend #2 45

Friend #3 15

Friend #4 -50

Compute each of the following (show all your steps):

a.

b. 3

c. ( 3)

d. !

e. ( )!

3. What is the scale of measurement for each of the following?

a. Your favorite sports team.

b. Amount of time it takes to respond to a stimulus.

c. Heart beat per minute.

d. Scores on the verbal section of the GRE, which ranges from 130-170.

4. For each of the following decide whether it is a correlational study or an experiment. If it is a correlational study, identify the variables whose relationship is being determined. If it is an experiment, identify the independent and dependent variables.

a. After administering a test of self-esteem to all the 6th graders in a school, the school psychologist has 6th grade teachers monitor the number of times each 6th grader voluntarily participates in class (answering questions, offering opinions) and determined the lower the self-esteem score of the child, the less they participated.

b. A cognitive psychologist examined the effect of noise on learning. He had half of the participants study five pages of textbook material in a noisy room, while the other half studied the same amount of material in a quiet room. Then, all participants took a test and their scores were recorded.

c. Dr. Freed is interested in studying the effect of heat on mood. Half of the participants in her study sat in a room set to 70F while they completed a mood questionnaire, while the other half completed the questionnaire in a room set to 90F.

Those in the 90F room rated themselves as being more frustrated than those in the 70F room.

5. For Question 4c above, where Dr. Freed found that participants who had been in the 90F room rated themselves as being more frustrated than those in the 70F room, explain how the difference in rated frustration in the two groups may have been:

a) caused by the treatments

b) due to sampling error

6. Use the summation notation to express each of the following (i.e. you are writing the following in symbols):

a. Add 4 to each score, then add the resulting values.

b. Add up all the scores, then square the sum. Subtract 5 from the squared value.

c. Square each score, then add up the squared values, then add 10 to the sum.