E&R T-Tests

what are t-tests used for?

to compare pairs of means

what are the 3 main types of t-tests?

1. one sample

2. paired sample (dependent)

3. independent

how are t-tests calculated?

by ratio

what is the ratio for t-tests?

between groups variance(large number)/ error variance(small number)

what do you want the observed t-value to be?

large

what do you want the variation to be in t-tests?

small

how can you make the t-value big?

1. increase group variance

2. decrease error variance

what is a one sample t-test used for?

to comepare a sample means with a known value or hypothetical population mean

what are the hypotheses for a one sample t-test?

H0- there are no significant differences between the two means (u = u₀)

H1- there is a significant difference between the two means (u ≠ u₀ )

how can you find the t-value without the formula?

use the t-table

when do you reject the H0 and accept the H1 with one sample t-tests?

when the t-value is past the critical value and in the rejection region (shaded)

what is a dependent sample or paired sample t-test used for?

to compare 2 means from the sample that were obtained at different times or under different conditions

what t-test will within subjects always use?

dependent or paired sample t-test

what are the hypotheses for dependent/paired sample t-test?

H0: no significant difference between the 2 means (u₁ = u₂ )

H1: is a significant difference between the 2 means (u₁ ≠ u₂ )

what is a dependent or paired sample t-test looking for?

just difference

what can you do with the two means in a dependent or paired sample t-test?

subtract them

if you subtract the 2 means in a dependent or paired sample t-test what are the new hypotheses?

H0: the mean difference score is not significantly different from 0 ( u₀ = 0)

H1: the mean difference score is significantly different from 0 (u₀ ≠ 0)

what is a dependent or paired sample t-test similar to?

a one-sample t-test

when do you fail to reject the H0 in a dependent or paired sample t-test?

if the t-value is past the t-critical and in region of rejection