Intro to statistical testing

Question 1

What is the first step in the research process?

Answer 1

Find a topic that you’re interested in and do some research into what has been studied before

Question 2

What is the second step in the research process?

Answer 2

Create an aim and hypothesis

Question 3

What is the third step in the research process?

Answer 3

Design the study, including type of experiment, experimental design, sampling technique, ethical considerations.

Question 4

What is the forth step in the research process?

Answer 4

Gain ethical approval from an ethics committee

Question 5

What is the fifth step in the research process?

Answer 5

Do a pilot study

Question 6

What is the sixth step in the research process?

Answer 6

Make refinements and conduct the study

Question 7

What is the seventh step in the research process?

Answer 7

Analyse the results using descriptive statistics to identify trends

Question 8

What is the eighth step in the research process?

Answer 8

Conclusion (based on red) - statistical test

Question 9

What are the final 3 steps in the research process?

Answer 9

Write up, Peer review, Publish Results

Question 10

What are inferential statistics?

Answer 10

A type of statistical analysis that allow researchers to determine whether they have found a significant result (i.e.that there is a difference or relationship between the variables they studied) or if it occured by chance (coincidence or fluke).

Question 11

What do inferential statistics allow us to do?

Answer 11

We can determine which of our hypotheses (alternative or null) should be accepted and which should be rejected based on them. They allow you to make inferences (i.e. Draw conclusions) about target population from a sample of data.

Question 12

What does it mean if the data is found to be significant?

hypothesis

Answer 12

They found a real difference/ correlation/ association, therefore can reject the null hypothesis and accept the alternative hypothesis.

Question 13

What does it mean if the data is found to be insignificant?

Answer 13

They have not found a real difference/ correlation/ association therefore accept the null hypothesis (coincidence).

Question 14

What does a significance level of p<0.05 mean?

Answer 14

It is concluding that it is significant but accepting that there is a probability of less than 5% that the results occurred by chance.

Question 15

What is the aim of statistical testing?

Answer 15

The purpose of statistical testing (inferential statistics) is to determine the likelihood (probability) that the effect/ difference/ relationship/ association found in the study is significant or due to chance.

Question 16

What do psychologists mean by ‘probability’?

Answer 16

Statistical tests work on the basis of probability (a numerical measure of the likelihood that a particular event will occur ranging from 0 to 1 where 0 indicated statistical impossibility and 1 indicates statistical certainty).

Question 17

What is a significance level?

Answer 17

This is the point at which the researcher can claim to have discovered a significant difference or correlation within the data. In other words, this is the point at which the researcher can reject the null hypothesis and accept the alternative hypothesis.

Question 18

Why can psychologists never be 100% certain about a particular result?

Answer 18

Psychologists can never be 100% certain about a particular result because they have not studied all members of the population under all possible circumstances.

Question 19

What values do psychologists compare in statistical tests?

Answer 19

In any statistical test that psychologists use, they compare the result of their test (the calculated value) to a critical value for the significance level that the psychologist has chosen.

Question 20

Why do psychologists compare these values in statistical tests?

Answer 20

If a significance level of p≤0.05 is chosen by a psychologist, comparing their calculated value to the critical value allows them to determine whether their results have a 5% or less probability of occurring by chance and are therefore significant, or whether they have more than a 5% probability of occurring by chance and so are not significant. Critical values are found in a critical values table.

Question 21

When would a p<0.05 significance level be used?

Answer 21

If the study is not one that involves a human cost and is not a one-off study that couldn’t be repeated in the future.

Question 22

What is a one-tailed study?

Answer 22

Directional hypothesis e.g. people will be happier

Question 23

What is a two-tailed study?

Answer 23

Non-directional hypothesis e.g. There will be a difference

Question 24

What is a calculated value?

Answer 24

The number achieved from a statistical test e.g. the sign test

Question 25

What is a critical value?

Answer 25

Each statistical test has its own critical values table where we can find the critical value to compare our calculated value to.

Question 26

When should you use the sign test (3 rules)?

Answer 26

1. researchers investigating difference
2. a related design
3. nominal data

Question 27

What is the difference between a related and unrelated design?

Answer 27

Related: matched pairs, repeated measures
Unrelated: independent design

Question 28

What is the first step of the sign test?

Answer 28

Identify the your 3 categories of results (e.g. better before, better after, no difference)

Question 29

What is the second step of the sign test?

Answer 29

Calculate the number of participants in each category

Question 30

What is the third step of the sign test?

Answer 30

Assign the no difference category a 0 sign

Question 31

What is the forth step of the sign test?

Answer 31

Assign one of the other two categories a + sign and the other a – sign.

Question 32

What is the fifth step of the sign test?

Answer 32

Out of the + and – sign categories, identify the category with the smaller number. This number is S.

Question 33

What is S (sign test)?

Answer 33

The calculated value