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Psy 210 Fall 2007
Final Exam
Tuesday Dec 11, 2007
Instructor: Kim Barchard
1. In the following frequency table, how many people obtained an Extraversion score of 3?
(1 mark)
Extraversion
1
2
3
4
5
6
Frequency
1
1
1
2
3
4
2. Which of the following represents the ordinal level of measurement? (1 mark)
a. Height in inches
b. Golf scores
c. Conscientiousness measured in T-scores
d. Number of coffee cups a person owns
e. Major in university (where accounting = 1, anthropology = 2, etc)
3. Calculate the mean of the following numbers: 10
(1 mark)
17 12
17
Show all your work.
4. A sample of 25 people are measured, and the sample range is calculated to be 10. If the
range is calculated for the entire population of 1000 people, it will almost certainly be
(1 mark)
a. less than 10
b. 10
c. more than 10
d. more than 10 but less than 25
e. 25
f. more than 25
5. Two fair dice are rolled. What is the probability that one of these dice is a 4 and the other is
a 5? You may solve this problem any way you want. You do NOT have a show your work
to get full marks, but if you do show your work, you may receive partial credit if your answer
is incorrect. (2 marks) Hint: if you are not positive that you have calculated this correctly,
check your work using another method.
6. The sample standard deviation (1 mark)
a. tells you how far spread out the numbers are in the sample
b. provides an estimate of how far spread out the numbers are in the population
c. tells you if the numbers are near the mean or far from the mean, on average
d. all of the above are true
7. In Dr. Leaf's course, the midterm has a mean of 45 and a mode of 55. This data is (1 mark)
a. positively skewed
b. not skewed
c. negatively skewed
8. Margaret has an IQ of 106. What is her z-score? (1 mark) Show all your work.
9. When the sample size is large, the sampling distribution of the mean has a (1 mark)
a. normal distribution
b. positively skewed distribution
c. symmetric bimodal distribution centered around the sample mean and the population
mean
10. A statistic is said to be relatively efficient if its _______________ is smaller than that of
another statistic that could be used to estimate the same population parameter. (1 mark)
a. outlier influence
b. population parameter
c. mean deviation
d. standard error
11. What does the symbol "p" mean? (1 mark)
a. probability of rejecting a false null hypothesis
b. population value of the correlation coefficient
c. probability that the null hypothesis is true
d. probability of getting results like these or more extreme than these if you were to
repeat the study in a new sample
e. probability of getting results like these or more extreme than these, given that the null
hypothesis is true
12. Imagine that a 95% confidence interval for the population mean is [ -2.3, 4.5]. If a researcher
used this confidence interval to test the null hypothesis that the population mean was 0 (using
a two-tailed test with alpha = .05), would they retain or reject the null hypothesis? (1 mark)
a. Retain
b. Reject
c. The answer cannot be determined from the information given. If you select this option,
state what additional information is needed.
13. Calculate P(Type II error given rejected Ho) or state that it cannot be calculated. (1 mark)
14. Jocie wants to examine the accuracy rate for a new data entry technique. Using a one-sample
t-test, she will compare the accuracy rate for the new technique with the accuracy of an old
data entry technique (its accuracy is .95). Each participant enters 10 data sheets, while being
supervised by one of six research assistants.
Would power increase or decrease if Jocie asked her research assistants to follow a script, to
reduce variability in how the study is administered? (1 mark)
a. increase
b. decrease
c. no change
15. In which of the following situations would an independent sample t-test be appropriate?
(1 mark)
a. Compare scores in your sample with the national average on Extraversion
b. Compare husbands and wives in terms of climbing skill
c. Compare men and women in terms of interest in math
16. The standard error of the difference of the means is the ______________________________
of the sampling distribution of X-bar1 – X-bar2. (1 mark)
17. A research paper wrote the following: "Students who completed the study habits training
obtained higher average grades than students who did not complete the training (t(39) = 3.55,
p < .05)." Answer the following questions. (1 mark each)
Was the test one-tailed or two-tailed?
What was t-obtained?
Did the researchers reject or retain the null hypothesis?
18. In the following data set, what is the pooled variance? (1 mark) Select one of the multiple
choice answers on the left. You do NOT have to show your work.
a. between 10 and 15
b. 15
c. between 15 and 20
d. between 100 and 250
e. 250
f. between 250 and 400
Mean
SD
N
Men
10
10
12
Women
15
20
18
19. In the question above, if the researcher used a one-tailed test with alpha = .01, what is
t-critical? (2 marks)
20. Among children aged 3 – 14, what is the relationship between age and height? (1 mark)
a. perfect positive
b. moderate positive
c. no relationship
d. moderate negative
e. perfect negative
21. Write the null hypothesis that the population correlation is zero, using all the correct symbols
and notation. Be very careful how you write the symbol for the null hypothesis, and be very
careful how you write the symbol for the population correlation. (1 mark)
22. If the correlation between two variables is .6, what proportion of variance in one variable can
be accounted for by the other variable? Assume that the relationship between the two
variables is linear. (1 mark)
23. In a positive relationship, as one variable increases, the other variable tends to (1 mark)
a. increase
b. decrease
c. reduce its variability
d. increase its variability
Name _________________________________