SCHOOL OF SOCIAL SCIENCES, MEDIA & COMMUNICATION
LEVEL 2
X2004 – Statistics for Psychology
DATE and TIME:
12 January 2009, 9:30am – 11:35am
DURATION: 2 Hours + 5 minutes reading time
PAPER SETTER: Dr. Stuart Wilson
INSTRUCTIONS
Each student should attempt all questions. For multiple choice
questions, students should indicate their answer by circling their
chosen option. For part two, students should provide their answer in the
space provided. If more space is needed, use the rear of the paper. If
you use the rear of the paper, please make this clear. STATISTICAL
TABLES ARE ATTACHED TO THE BACK OF THE EXAM.
Show all calculations.
Matriculation Number:
__________________________________________________
PART 1
Please circle your chosen answer. If you change your mind, make it clear what your
final answer is
1. MENSA is an organisation for people with high IQs. Their annual report
states that the average IQ in the UK is 100, with a standard deviation of
15. Mensa only accepts people who have an IQ score that is in the top 2%
of the population. What is the minimum IQ score that a person would
need to get to be eligible to join Mensa?
a. 130.9
b. 130
c. 102.6
d. 115.2
2. A z-score is defined as:
a. The number of standard deviations a score is away from the distribution mean
b. The population mean of a z-distribution
c. The standard error divided by the standard deviation of a sample mean
d. Both “a” and “c”
3. Professor Allen is interested in the effects that exercise has on current
mood. She recruits students and randomly allocates 20 to an “exercise”
condition and 20 to a “no exercise” condition. After an hour of either
exercising or not, current mood is assessed on a scale ranging from 0 to
100, with the exercise group averaging a mood of 62 (standard deviation =
18) and the no-exercise group averaging 41 (standard deviation 14).
Assuming that this is interval level data and that parametric assumptions
have been met, what is the most appropriate test to conduct in order to
determine whether exercising effects mood?
a. t-test for independent samples
b. t-test for related samples
c. One-way ANOVA for related samples
d. Chi-Square test.
please turn over
4. Pearson’s Product Moment Correlation Coefficient is a ____________
test of __________ that focuses on z-scores
a. Parametric; Difference
b. Non Parametric; Difference
c. Parametric; Correlation
d. Non Parametric: Correlation
5. The standard deviation of a distribution of sample means is also known
as:
a. Z-Score
b. Mean Deviation
c. Population Estimate
d. Standard Error
6. What effect will increasing the sample size have on a distribution of
sample means?
a. The standard error will decrease
b. The standard error will increase
c. The standard error will neither increase nor decrease, but the mean will
increase
d. The distribution will become skewed
please turn over
7. When using an ANOVA design you are ideally looking for the
__________ to be large and the __________ to be small.
a. Within Groups Variation/Between Groups Variation
b. Between Groups Variation/Within Groups Variation
c. “Treatment” effects/Errors of measurement
d. Both b and c
8. When specifying a regression line, what two values must be known?
a. The sample size and the standard error
b. The point of interception and the slope of the line
c. The slope of the line and the point of interception of the line
d. The slope of the line and the correlation coefficient of the line
please turn over
9. Which one of the following scattergrams (based on a Pearson’s Product
Moment Correlation Coefficient) shows a non-significant positive
correlation?
a.
b.
c.
d.
Figure 1
Figure 2
Figure 3
Figure 4
r = 0.85, p = 0.01
r = - 0.12, p = 0.95
Figure 2
Figure 1
r = - 0.79, p = 0.01
Figure 3
r = 0.02, p = 0.99
Figure 4
10. A p-value is an indication of:
a. The likelihood that you would have found the results that you did if the null
hypothesis was true
b. The likelihood that your experiment is internally valid
c. The likelihood that you will obtain the same results if you did the experiment
again
d. The likelihood that your dependent variable is reliable
please turn over
Part 2
Answer in the space provided
1.
Choose three criticisms of traditional experimental research that have
emerged from the qualitative paradigm. Outline what the criticisms are and the
ways in which qualitative research addresses them (10 marks).
please turn over
2. A student conducts a repeated measures ANOVA on SPSS and
gets the following two tables as output. “Factor 1” had 3 levels.
Mauchly's Test of Sphericityb
Measure:MEASU
RE_1
Epsilona
Within
Subjec
ts
Effect
factor1
Mauchly's
Approx.
W
Chi-Square
.842
6.348
df
Sig.
2
Greenhouse
Huynh-
Lower-
-Geisser
Feldt
bound
.052
.864
.901
.500
Tests the null hypothesis that the error covariance matrix of the orthonormalized
transformed dependent variables is proportional to an identity matrix.
a. May be used to adjust the degrees of freedom for the averaged tests of significance.
Corrected tests are displayed in the Tests of Within-Subjects Effects table.
b. Design: Intercept
Within Subjects Design: factor1
Tests of Within-Subjects Effects
Measure:MEASURE_1
Type III Sum
Source
factor1
of Squares
Sphericity Assumed
df
Square
F
Sig.
28.832
2
14.416
41.534
.000
28.832
1.728
16.689
41.534
.000
Huynh-Feldt
28.832
1.802
15.996
41.534
.000
Lower-bound
28.832
1.000
28.832
41.534
.000
26.379
76
.347
26.379
65.650
.402
Huynh-Feldt
26.379
68.492
.385
Lower-bound
26.379
38.000
.694
GreenhouseGeisser
Error(factor1 Sphericity Assumed
)
Mean
GreenhouseGeisser
a. How should this student present these results in her dissertation? (5 marks)
please turn over
3.
A student conducts research into the correlation between scores on
a measure of pre-test anxiety and exam performance.
a. Fill in the table and work out the Pearson’s Product Moment
Correlation Co-Efficient (formula given below) (10 marks)
Pre-test
anxiety (x)
Deviation
from
mean (d)
Exam score
(y)
Zx
Deviation
from
mean (d)
Zy
51
18
36
32
45
21
56
12
63
11
21
43
52
22
Mean (x)
Mean (y)
ZxZy
Σ (Zx Zy) =
sd (x)
sd (y)
r=
Σ (zxzy)
N–1
please turn over
<space for working>
r = ____________________________________________________
please turn over
4.
Professor Pollard is interested in whether Science students and Arts
students differ in the degree to which they believe in “love at first
sight”. To test this, she conducts a survey. In the survey she asks
each student whether or not they believe in “love at first sight”. Her
results can be seen below.
Science students
Arts students
Believe in “love at first
sight”
8 (
)
35 (
)
Do not believe “love at
first sight”
41 (
)
17 (
)
She decides that the best way of analysing this data is by using a Chi-Square.
a. Work out what the expected frequencies (E) would be for each cell under
the null hypothesis. Insert the expected frequencies in the table next to the
observed frequencies. (4 marks)
E = Row total x Column Total
Overall Total
please turn over
b. Work out the chi-square value. The formula for working out a chi-square
is:
(5 marks)
please turn over
c. What would a significant Chi-Square indicate? (3 marks)
end of exam