Chapter 10: Independent-Measures T-Tests

Question 1

what p-values represent a significant effect

Answer 1

less than 0.05

Question 2

reporting results in the literature

Answer 2

• includes the effect found, mean, standard deviation, t-value, p-value, alpha level, confidence interval, cohen’s d, r2
• ex. babies looked at attractive faces 3 seconds longer than unattractive faces, (M = 13 seconds for attractive faces out of the 20-second interval, SD = 3 seconds). This 3-second difference was statistically significant t(8) = 3.0, p = .0170 at the .05 level, 95% CI [.69, 5.31], d = 1.00, R2 = .53.

Question 3

what does the t-value represent in confidence intervals

Answer 3

corresponds to the t-value associated with the alpha level

Question 4

interpretation of the confidence interval

Answer 4

if we sampled again, we would expect that ___% of samples’ C.I.s of this size to contain the true population mean

Question 5

independent-measures designs

Answer 5

Allow researchers to evaluate the mean difference between two populations using data from two separate samples

Question 6

null hypothesis for the independent-measures t-test

Answer 6

states that there’s no difference between the two means
μ₁-μ₂ = 0

Question 7

alternative hypothesis for independent-measures t-test

Answer 7

μ₁-μ₂ ≠ 0

Question 8

pooled variance

Answer 8

Represents the average variability across the two samples

Question 9

pooled variance formula for independent-measures

Answer 9

s²p= SS₁ + SS₂/ df₁ + df₂

Question 10

estimated standard error formula for independent-measures t-tests

Answer 10

S (m₁-m₂)= √s²p/n₁ + s²p/n₂

Question 11

t-value formula for independent-measures

Answer 11

t= (m₁-m₂)- (μ₁-μ₂)/ S(m₁-m₂)

Question 12

function of the value of Cohen’s d or r² for independent-measures studies

Answer 12

helps to describe how much difference there is between the two treatments or groups

Question 13

confidence intervals for independent-measures tests

Answer 13

CI= M1-M2 +/- ts (m1-m2)