Question

A researcher wants to look at how exercise affects mood. she anticipates that exercising more will improve mood. she has a group of participants run for 30 minutes and then has them rate how happy they feel on a scale from 0-10 and obtains the following scores: 9,7,8,5,7,6,4. The population mean on this Likert scale is 5. Use a t-test to determine if the treatment is statistically significant/you should reject the null hypothesis at the .05, .01, and .001 p-values.

Answer 1

A Likert-type question (or ‘item’) asks respondents to select one of several (usually four or five) responses that are ranked in order of strength. Here’s an example:

Indicate what you think about the following statements using the scale below:
(1) Strongly Agree; (2) Agree; (3) Neither agree nor disagree; (4) Disagree; (5) Strongly Disagree

a. Apples are rubbish	1	2	3	4	5
b. Yoghurt is my favourite food	1	2	3	4	5
c. Beans are evil	1	2	3	4	5
d. Fish fingers and custard taste great	1	2	3	4	5

Each of these items measures a variable, i.e., a construct about which we want to learn more. Sometimes, sets of similar items are dispersed in the same questionnaire. This helps researchers to probe different aspects of the same construct (or ‘latent variable’), by putting together information from all the related items. I will not go into any of this in more detail here, but if you want to find out more, this posthas some additional information.

Likert scales are very frequently used to measure constructs like satisfaction rates, attitudes towards different things, and more. They are very flexible and very useful, provided you use them carefully.