Word Doc Week 4

Question 1

What is a t-test?

Answer 1

• One of the simplest of statistical tests
• Used to test questions around mean differences
• Is there a significant difference between two means?

Question 2

Three types of t-test

Answer 2

• Single-sample t-test
• Independent samples t-test
• Paired or matched or repeated samples t-test

Question 3

Null Hypothesis

Answer 3

• States that there is no relationship between the two variables being studied
• Results are due to chance
• Results are not significant in terms of supporting the idea being investigated

Question 4

Alternative Hypothesis

Answer 4

• States that there is a relationship between the two variables being studied
• The results are not due to chance
• They are significant in terms of supporting the theory being investigated.

Question 5

Single-Sample t-test

Answer 5

• Is there a statistically significant difference between your sample mean and a known comparative population or large-sample value?

Question 6

Independent Samples t-tests

Answer 6

• Is there a statistically significant difference between two sample means taken from a categorical/grouping/nominal variable in your sample?

Question 7

Paired samples t-test

Answer 7

• Is there a significant difference between the means associated with two separate, complete variables in your data
• Is there a difference between the means associated with a pair of variables.
• Used to test paired, repeated or matched data
• Each subject has given a pair of values
• Each value is represented in separate variables in the data

Question 8

How to do t-tests in SPSS

Answer 8

• Two different versions are provided
  
  • ​Equal variances assumed
  • Equal variances not assumed.
• Look at Sig. for equality of variance test first.
  
  • If p < .05, it means that homogeneity of variance has been violated
  • The variance is not equal
• Therefore use Equal variances not assumed.
  
  • If p > .05 it means that homogeneity of variance has been met
  • Variance is approximately equal; therefore use Equal variances assumed.

Question 9

How to write up results of t-test - Question This??

Answer 9

The homogeneity of variance assumption was found to be met, p = .67; therefore, statistical testing assumed equal variances. Men were found to have significantly higher occupational prestige scores than women, t(1416) = 2.34, p = .019.

Question 11

Repeated Measures Designs

Answer 11

• Also Known As within samples designs
• Each subject gives you daa on every level of the independent variable

eg: taking BSL scores before and after eating

Question 12

Are there Alternative Repeated Measures Designs?

Answer 12

• Matched samples
• Randomised blocks

eg: compare weight loss with:

• Diet only
• Exercise only
• Combination Diet & Exercise

Question 13

How to write up Paired Sample t-test

Answer 13

A paired-sample t-test revealed no significant difference between the number of years of formal education for mothers and fathers, t(973) = 0.07, p = .94.

Question 14

Single-sample (one-way) t-test

Answer 14

• Not so common
• Used to test your sample mean against a comparison value
  
  • An established normative score
  • Another researcher’s result
  • A known population parameter
• A single-sample t-test revealed a significant difference between the sample mean for number of respondents’ children (M = 1.90, SD = 1.77) compared against the hypothesised population value of 2, t(1508) = 2.17, p = .03.