Cream Pack 3

Question 1

Why is the level of measurement important?

Answer 1

Knowing the level of measurement helps you decide what descriptive statistics and which inferential statistical test is appropriate for your
data.

Question 2

What are the 3 levels of measurement?

Answer 2

• nominal
• ordinal
• Interval

Question 3

What is nominal level data?

Answer 3

Frequency counts in mutually exclusive categories.

Question 4

Give an example of nominal level data

Answer 4

A researcher recording the frequency counts of people’s favourite colours.

Question 5

What is ordinal level data?

Answer 5

Ordering data in a certain way. However the exact difference between each point on the scale is not known.

Question 6

Give an example of ordinal level data

Answer 6

Ranking people’s test scores.

We know the position but not exactly how much better or worse each person is

Question 7

What is interval level data?

Answer 7

Numbers that come from a scale of equal intervals.

Question 8

Give an example of interval level data

Answer 8

Measuring people’s height in cm

Question 9

Which is the three levels of measurement contains the most information?

Answer 9

Interval data

Question 10

Which is the three levels of measurement contains the least information?

Answer 10

Nominal data

Question 11

The number of words recalled by participants in each of two conditions: when they are given 30 seconds or
45 seconds to memorise them.
What level of measurement are implied in the data collected?

Answer 11

Ordinal or interval

Question 12

The time taken in seconds for participants to read a script which is handwritten as opposed to typed.

What level of measurement are implied in the data collected?

Answer 12

Interval

Question 13

A dental receptionist is asked to judge whether people in the waiting room are ‘calm’ ‘anxious’ ‘very anxious’ or ‘hysterical’

What level of measurement are implied in the data collected?

Answer 13

Nominal

Question 14

Distance two participants stand apart when asked to take part in an intimate conversation, measured from photos.

What level of measurement are implied in the data collected?

Answer 14

Interval

Question 15

What is ratio level of measurement?

Answer 15

A ratio scale of measurement is simply an interval scale in which it is impossible to get a negative value.
E.g. it is impossible to have a negative reaction time.

Question 16

How can the levels of measurement be converted?

Answer 16

Interval data can be converted into ordinal or nominal data.
Ordinal data can be converted into nominal.
Every time we convert information is lost.

Question 17

Nominal level data is made up of data in ‘mutually exclusive” categories. What are mutually exclusive categories?

Answer 17

Categories that do not overlap and only mean one thing.

Question 18

Your friend argues that, since she came top in each of the three maths tests held in her class this year, she must be far better than all the other students. What might you point out to her?

Answer 18

It is ordinal data so the exact difference between her scores and the students below her is not known.

Question 19

What is probability?

Answer 19

a numerical measure of chance.

It represents how likely it is that the results are due to chance.

Question 20

Why do researchers use inferential statistical tests?

Answer 20

Researchers use inferential statistical tests to help them assess the probability that the difference or correlation they observed in the
results is statistically significant (due to chance) or not.
i.e. whether to accept or reject the null hypothesis

Question 21

Name 4 inferential statistical tests

Answer 21

• Chi - Squared
• Wilcoxon Signed ranks
• Mann- Whitney U
• Spearman’s ho correlation coefficient

Question 22

What is the traditional level of significance chosen by psychologists?

Answer 22

(p ≤ 0.05) 5% level
OR
95% significant

Question 23

What does the (p ≤ 0.05) significant level mean?

Answer 23

The probability (p) of the results occurring due to chance is less than or equal to (≤) 5% (0.05).

Question 24

What would happen if the probability of the results occurring due to chance is greater than the 5% level?

Answer 24

Researchers would accept their null hypothesis and state that any difference or correlation seen in the results was due to chance.

Question 25

What is the significance level?

Answer 25

The probability at which the null hypothesis can be rejected

Question 26

State what the observed value means

Answer 26

The value calculated by the researcher themselves

Question 27

State what the critical value means

Answer 27

Pre-calculated table of values

Question 28

What are the 5 statements of significance?

Answer 28

* the observed and critical values used and which was bigger * the sample size * the significance level used * whether the one or two tailed test was used * which hypothesis was accepted

Question 29

When does a researcher choose the 10% level? p≤0.1

Answer 29

This is used when a researcher does not need a strict level of significance e.g. when beginning a new area of research

Question 30

When does a researcher choose the 1% level? p≤0.01

Answer 30

-This is used when a researcher needs a very strict level because any mistakes in the research could have serious consequences

Question 31

What is the most strict level of significance?

Answer 31

p≤0.01

Question 32

What is the least strict level of significance?

Answer 32

p≤0.1

Question 33

What is a Type 1 error?

Answer 33

Accepting the alternative hypotheses when the results are actually due to chance. (false positive) Say there is an effect when there isn't one.

Question 34

What is a Type 2 error?

Answer 34

Accepting the null hypothesis when the results were not due to chance. (false negative) You say the is not an effect when actually there is.

Question 35

What type of error is a researcher more likely to make using the 10% significance level?

Answer 35

Type 1 error

Question 36

What type of error is a researcher more likely to make using the 1% significance level?

Answer 36

Type 2 error

Question 37

What does p>0.5 mean?

Answer 37

The probability of results being due to chance is more than 5%

Question 38

If results were found to be not significant at p<0.05 which hypothesis would have to be accepted?

Answer 38

Null hypothesis

Question 39

How do researchers judge the significance of their results?

Answer 39

Using inferential statistical tests then compare the observed value from the critical value

Question 40

What effect does a one-tailed test compared to a two tailed test have on whether the results are judged to be significant?

Answer 40

On a statistical basis it is easier for a one tailed test rather than two tailed as you know the exact direction.

Question 41

What are non-parametric tests of significance?

Answer 41

These are the statistical tests carried out when dealing with ordinal or nominal levels of measurement.

Question 42

What are the 3 decisions needed to be made when selecting an appropriate statistical test?

Answer 42

1) What are you testing for? (difference or correlation?) 2) Level of measurement (nominal or ordinal?) 3) Unrelated (independent groups) or Related data? (repeated measures + matched pairs)

Question 43

Table for Non-parametric test and their conditions for use

Answer 43

Question 44

Practice justifying your choice of test.

Answer 44

State the test that should be chosen. | And give reasons. (Linked to the three decisions) explaining detail why.