Inferential Stats

Question 1

Distributions

Answer 1

how the typical value and the spread of scores relate to one another

Question 2

Normal distribution

Answer 2

scores spread equally around the mean, mean roughly in the middle

Question 3

Skewed to the right distribution

Answer 3

positively skewed
bulk of scores at lower end
mean slightly to the left of the middle

Question 4

Skewed to the left distribution

Answer 4

negatively skewed
bulk of scores at higher end
mean slightly to the right of the middle

Question 5

68-95-99.7 rule

Answer 5

idea that when scores are normally distributed most scores will be spread within 2 SDs from the mean
68 % scores will be within 1 SD
95% scores will be within 2 SD (technically 1.96SD)
99.7% scores will be within 3 SD

Question 6

Predicting the population mean from the sample mean

Answer 6

use sample mean and SD
calculate 95% confidence interval (use 95 part of rule)
mean +or- 1.96 x SD divided by √n

Question 7

Trade-off for 95% confidence interval between:

Answer 7

certainty of correct pop. mean
how small interval is
(chance we’re 5% wrong)