Choosing a statistical test

Question 1

What are the 3 key questions when choosing a statistical test?

Answer 1

Testing for difference or correlation, related or unrelated design and nominal, ordinal or interval level data

Question 2

What do the hypothesis for testing for difference predict?

Answer 2

The group/condition scores will differ

Question 3

How are the results of a test for difference displayed?

Answer 3

A bar chart

Question 4

What does the hypothesis for a test of a correlation predict?

Answer 4

There will be a positive or negative correlation

Question 5

How are the results of a test for correlation displayed?

Answer 5

A scattergram

Question 6

What are the types of tests for difference?

Answer 6

A related or unrelated design

Question 7

Where does related data come from?

Answer 7

The same participants (repeated measures) and matched pairs

Question 8

Where does unrelated data come from?

Answer 8

Independent groups - including a comparison of 2 different things

Question 9

What are the types of data?

Answer 9

Nominal, ordinal and interval

Question 10

What is nominal data?

Answer 10

When particpants are put in a category - yes or no / attachment type

Question 11

What is ordinal and interval data?

Answer 11

A participant has a numerical score for each particpant

Question 12

What is interval data?

Answer 12

An agreed way or measuring the variable, no judgment, intervals between points on scale are fixed and can make mathematical comparison

Question 13

What are examples of interval data

Answer 13

Time taken and height

Question 14

What is ordinal data?

Answer 14

Different possible ways of measuring variable involving a degree of judgment where intervals between points on the scale are not ‘fixed’ so can’t make mathematical comparison

Question 15

What are examples of ordinal data?

Answer 15

Strength of attachment and how aggressive someone is

Question 16

What is the main difference between interval and ordinal data?

Answer 16

Interval is objective and ordinal is subjective

Question 17

What is the pneumonic for remembering statistical tests?

Answer 17

Carrots Should Come Mashed With Swede Under Roast Potatoes

Question 18

What is the rule of rs?

Answer 18

If a test name has an r in it, the calculated value should be equal to or more than the critical value

Question 19

What measure of central tendency should you use with interval data?

Answer 19

The mean

Question 20

What measure of central tendency should you use with ordinal data?

Answer 20

The median

Question 21

What are the types of tests?

Answer 21

A one tailed or two tailed test

Question 22

When do you use a one tailed test?

Answer 22

When there is previous research suggesting a direction

Question 23

What do the results for a one tailed test need to be to be significant?

Answer 23

In the most extreme 5% at one specified end of distribution

Question 24

When do you use a two-tailed test?

Answer 24

When there is no previous research or findings are insignificant

Question 25

What must the results of a two tailed test be to be significant?

Answer 25

In the most extreme 2.5% at one of the 2 ends of a distribution to be significant

Question 26

What are the types of errors?

Answer 26

Type 1 and type 2

Question 27

What is a type 1 error?

Answer 27

A false positive when you think there is a difference but there isn’t

Question 28

What is a type 2 error?

Answer 28

A false negative, thinking there is no difference when there is