Independent t-test

Question 1

Used for…?

Answer 1

Difference questions
DV = continuous
IV = categorical
Between-subjects design

Question 2

What does an independent t-test do?

Answer 2

Compares the difference between means of 2 independent groups

Question 3

What does p indicate?

Answer 3

Percentage chance that the null hypothesis is true (there is no difference)

Question 4

Reporting a significant result

Answer 4

IV1 (mean = …, SD = …)
Compared to IV2 (mean =… , SD = …), t(df) = … , p = … What this suggests
95% confidence intervals and interpretation

Question 5

Reporting an insignificant result

Answer 5

IV1 (mean = …., SD = … )
Wasn’t significantly different from IV2 (mean = … , SD = …)
t(df) = … , p = …
This means we cannot reject the null
Cannot say for sure if there is an effect

Question 6

Assumptions for independent t-test

Answer 6

Data must be normally distributed
Spread of scores is relatively equal in both groups (Levene’s Test for Equality = >0.05 variances equal)
If not equal use variances not equal

Question 7

df for independent t-test

Answer 7

df = n - 2

Question 8

Type 1 error

Answer 8

p < 0.05
Conclude that there is a difference/relationship
There isn’t

Question 9

Type 2 error

Answer 9

p > 0.05
Conclude that there isn’t a difference/relationship
There is