QUESTIONS AND
ANSWERS
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PYC3704/201
So what this formula tells you is that the mean of the x-values is calculated by adding them up and dividing
the result with n (which is equivalent to multiplying the result with 1/n).
Let us test this on a small set of data (which can be regarded as different measurements of a variable 8x9).
X 14 12 11 22 15 10 15 17 13 15
Here the sum of x would be: Σx = 14 + 12 + 11 + 22 + 15 + 10 + 15 + 17 + 13 + 15 = 144.
Because there are 10 values for x, we know that n = 10. So if we substitute this in the formula:
1 1
� 㕥̅
= ∑� 㕥 = × 144 = 14.4
ÿ 10
For a more advanced example, let us calculate the value of the sample standard deviation, usually
indicated by s. The formula for s (given in Appendix C in the Guide) is as follows:
∑(� 㕥 )−2 �㕥̅
Ā= :
ÿ−1
This formula describes the calculation process which you need to perform to get the standard deviation of
the sample of data above. It tells you that you have to subtract the mean (x̄ ) from each value of x, square
the result, and add these together. This total you divide by n-1. The square root (√) of this result then gives
you the value of s. If you do not take the square root here, you will in fact end up with s2, which is referred
to as the sample variance.
A good way to calculate a somewhat complicated sum like Σ(x - x̄ )2 by hand is to first arrange the data in
a table, like below:
The second column presents the values of x, and the third column shows the values of each x with the
mean (which we calculated above as x̄ = 144.4) subtracted from that value of x. The fourth column gives
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the squares of each of these new values (that is, the column 3 values multiplied with themselves). We are
interested in the sum of these (usually referred to as the sum of squares), which adds to 104.4, indicated
in the bottom row of the table. This result therefore indicates that Σ(x - x̄ )2 = 104.4.
When you use tables like this, make sure you understand how to use this notation. For example, you have
to know that if you were working with two variables x and y, Σxy and ΣxΣy will not produce the same result
(see Appendix E in the PYC3704 Guide, especially p. 176).
To determine the standard deviation, we should substitute the sum of squares we calculated above in the
formula for s, as follows:
Note how it takes many words to explain this process, and that it can be difficult to express it in a very
exact way in words. The formula is a very concise and exact expression of the process, which is why we
need to use it.
3. Feedback for Assignment 01 of the second semester of 2020
For your convenience, each question is given followed by the appropriate answer and an explanation
of the correct response. Work your way systematically through these, comparing it with your own
answer. Even if you chose the correct alternative, you may find that the explanations we give are useful.
Try to understand the explanations. Many of the items require insight, not just factual knowledge. You
will not pass this course if you try and memorise the questions and answers!
Question 1
Which of the options below provides the best description of the main purpose of quantitative research in
psychology? Its purpose is to - - - - -.
1. develop theories that explain the relationships among observed aspects of human behaviour and
mental processes
2. develop predictions about human behaviour of which we can be applied with absolute certainty
3. describe and classify aspects of humans and human behaviour
4. develop hypotheses about relationships that may exist among various constructs
➔Answer: Option 1 is correct.
The ultimate aim of research is to explain the phenomena we see, and this is done by way of theories.
These may be used in prediction but not with 'absolute certainty' as claimed in Option 2. Research begins
with description and classification (Option 3) but this is not its ultimate purpose. Hypotheses are developed
in order to test the probability of certain explanations (as stated in Option 4), but this is a step in the
research process, not its purpose.
Question 2
Empirical knowledge is defined as - - - - -.
1. theories which explain why facts appear as they are observed to be
2. knowledge based on creative insights
3. direct experiences as they are caught in the moment of conscious awareness
4. information derived from careful observation and description of objects and events
➔Answer: Option 4 is correct.
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Empirical knowledge is the knowledge that you have obtained because you observed what is happening
or you have the personal experience of the event. Option 1 is wrong because empirical knowledge derive
from experience rather than theory. Option 2 and 3 are also wrong because neither of these fit to the
definition of 'empirical' knowledge.
Question 3
Operationalizing a construct means to - - - - -.
1. find an explanation for the construct to explain why it appears as it is
2. make an educated guess on how it relates to other constructs
3. determine the correct level at which it should be measured
4. devise a systematic procedure to make the construct observable, in such a way that we can
measure it
➔Answer: Option 4 is correct.
A construct is some event or entity which the researcher regards as being of importance in an explanation
of the phenomenon under investigation. In quantitative research, where data are treated in numeric form,
the problem is how to measure it, and the procedure used to achieve this is referred to as
operationalization. For example, one may suppose that persons with concentration problems are affected
by anxiety. To research this, some way will have to be found to measure each of the constructs 8ability to
concentrate9 and 8anxiety9, perhaps by developing suitable tests or observation methods.
Option 1 refers to the process of developing theories and Option 2 to the process of developing
hypotheses. Option 3 is fairly ambivalent but is not part of a definition of the process called
8operationalizing9.
Question 4
A theory is a(n) - - - - -.
1. explanation of observed facts and relationships among them
2. inspired guess or supposition about the relationships among constructs
3. careful description of the facts based on observations of objects or events
4. explanation of human behaviour based on literature
➔Answer: Option 1 is correct.
The word 8theory9 is used in scientific text to indicate an explanation of why facts are as they are, or how
they are connected (see Section 1.2.2 in the PYC3704 Guide).
Option 2 is wrong because this is actually a definition of a hypothesis. A hypothesis is a guess used to
explain something, whereas a theory will be based on the result of testing one or more hypotheses and
establishing their validity. Option 3 is wrong because while all scientific research should begin with a careful
description of phenomena based on observation to establish the facts (and this may include careful
measurements), a theory goes beyond this to explain why things are as they seem to be, or how and why
they are connected in certain ways. Theories are reported in the literature so that people can read about
it, but the theory as such is based on research, not on literature, so Option 4 is wrong.
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