Department of Industrial and Organisational Psychology
IMPORTANT INFORMATION:
This tutorial letter contains important information
about your module.
Define tomorrow. 1
, IOP2601/201/1/2018
CONTENTS
Page
1 Feedback on Assignment 01 2
2 Feedback on Assignment 02 5
3 Examination information 11
4 Appendix: Past examination paper 12
5 Conclusion 21
Dear Student
In this tutorial letter you will receive feedback on Assignments 01 and 02. Model answers are given
for the calculations. Please pay special attention to the mark allocation. For the multiple-choice
questions, the correct alternative, as well as a discussion on it, is given. Your task is to compare your
completed assignments with the memoranda to see where you made mistakes. Remember that the
feedback on Assignment 03 is given in the study guide.
We have also included more information on the examination in this tutorial letter. A copy of an
examination paper is included in the appendix as an example. By working through it, you will get a
good idea of what could be expected of you in the examination.
1. FEEDBACK ON ASSIGNMENT 01
This is the first compulsory assignment that you had to submit. It contributes 10% towards your final
mark. See page 16 in Tutorial Letter IOP2601/101/3/2018 for details on how to calculate your final
mark.
A full memorandum is provided here. Compare your answers with the following memorandum and
make sure that you understand this first part of Descriptive Statistics before you continue with the next
assignment on the rest of Descriptive Statistics and Inferential Statistics.
QUESTIONS 1–30 [30]
The correct alternatives are given in the second column next to the question number.
Item Answer Comments
1 2 False – assignment 3 is not compulsory and is a self-evaluation assignment
that should not be submitted. See page 16 of the tutorial letter 101/3/2018.
2 1 True – see page 17 of the tutorial letter 101/3/2018 and page 35 of the study
guide.
3 1 True – see page 13 of the tutorial letter 101/3/2018.
2
, IOP2601/201/1/2018
Item Answer Comments
4 1 True – the research process is discussed on page 35 of the study guide.
5 3 Figure 2 on page 22 of the study guide illustrates data analysis as the research
step that IOP2601 focusses on. Also, read the explanation provided on the
same page.
6 2 Interval width (interval size) is the distance between the upper class and the
lower class. The distance between 45 and 50 is 6.
Note: We start counting from 45 and not from 46. See page 47 of the study
guide, and pages 22 and 32 of Tredoux and Durrheim (2013).
7 3 The formula for the percentile rank is provided on page 32 of Tredoux and
Durrheim (2013) as:
𝑠𝑐𝑜𝑟𝑒 − 𝑅𝐿𝐿
𝑝𝑒𝑟𝑐𝑒𝑛𝑡𝑖𝑙𝑒 𝑟𝑎𝑛𝑘 = % 𝑏𝑒𝑙𝑜𝑤 + (𝑖𝑛𝑡𝑒𝑟𝑣𝑎𝑙 %)
𝑐𝑙𝑎𝑠𝑠 𝑖𝑛𝑡𝑒𝑟𝑣𝑎𝑙 𝑤𝑖𝑑𝑡ℎ
The substitution of the formula is explained on page 32 of Tredoux and
Durrheim (2013). Also see the exercises in activity 4.7 on pages 56 to 58 of
the study guide. Based on this, the percentage (%) below of a score of 76 is
70:
24 + 60 - 56,5 (16)
6
8 1 Using the substitution from the formula above, the real lower limit (RLL) is
56,5.
24 + 60 – 56,5 (16)
6
9 1 The formula for the percentile rank is provided on page 33 of Tredoux and
Durrheim (2013).
score of p = RLL + PR - % below(interval width)
interval %
10 3 The total of the scores in the distribution (sum of the frequency scores) is 50.
11 1 The mode is the most frequently occurring score in a dataset. See page 66 of
the study guide.
12 2 The median location formula is as follows:
(8 + 1)/2 = 9/2 = 4,5th position
See page 64 of the study guide.
3
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