Research Methods- Introduction to statistical testing

Question 1

Statistical testing -

Answer 1

Provides a way of determining whether hypotheses should be accepted or rejected.
In psychology, they tell us whether differences or relationships between variables are statistically significant or have occurred by chance.

Question 2

Sign test -

Answer 2

A statistical test used to analyse the difference in scores between related items (e.g. the same participant tested twice). Data should be nominal or better.

Question 2

What did researchers find after participants drank SpeedUpp compared to water?

Answer 2

They found a difference in the level of chattiness, with participants speaking more words after drinking SpeedUpp.

Question 3

Can the difference in chattiness between SpeedUpp and water conditions be immediately considered significant?

Answer 3

No, the difference may have occurred by chance, coincidence, or fluke, and further statistical testing is needed to determine significance.

Question 4

What statistical test can be used to determine if the difference in chattiness is significant?

Answer 4

The sign test can be used to determine if the difference is significant.

Question 5

What are the conditions required to use the sign test?

Answer 5

1. The study must be looking for a difference, not an association.
2. A repeated measures design must have been used.
3. Data must be organized into categories (nominal data), or converted into nominal data for the test.

Question 6

What does it mean if the experimental hypothesis is accepted at the 0.05 significance level?

Answer 6

It means there is less than a 5% probability that the results occurred by chance, and the researcher can be fairly confident the difference was due to the manipulation of the independent variable.

Question 6

What is the accepted level of probability in psychology for determining significance?

Answer 6

The accepted level of probability is 0.05, or 5%.

Question 7

When might researchers use a stricter significance level, such as 0.01?

Answer 7

Researchers use a stricter significance level (e.g., 0.01) in cases involving human cost, such as drug trials, or when the investigation is a one-off and cannot be repeated.

Question 8

What information is needed to find the critical value in the sign test?

Answer 8

1. The desired significance level (usually 0.05).
2. The number of participants (N value).
3. Whether the hypothesis is directional (one-tailed) or non-directional (two-tailed).

Question 8

What is the calculated value in statistical testing?

Answer 8

The calculated value is the number obtained after performing the statistical test.

Question 8

What is the critical value in statistical testing?

Answer 8

The critical value is the number from a table of critical values that the calculated value is compared to, to determine if the result is significant.

Question 9

How does the calculated value compare to the critical value in the sign test for the result to be significant?

Answer 9

For the sign test, the calculated value must be equal to or lower than the critical value for the result to be considered significant.