Exam Two

Question 1

When to reject the null

Answer 1

When the test statistic is greater than the critical value

Question 2

When to reject with p value

Answer 2

If the p value is less than the significance level

Question 3

When to use t scores v z scores

Answer 3

T scores for when we don’t know the population mean

Z scores for when we do

Question 4

Z score formula

Answer 4

(Sample mean - population mean)/ standard error

Question 5

Critical values

Answer 5

t.inv(proportion, df)

Question 6

Main critical values (z score)

Answer 6

90% CI: 1.645
95% CI: 1.960
99% CI: 2.575

Question 7

Increasing the sample size does what to margin of errors

Answer 7

Decreases, and therefore increases CI

Question 8

Special addition rule

Answer 8

Used when two events are mutually exclusive. Obtain any probability for a discrete random variable by knowing its probability distribution

Question 9

Expected value

Answer 9

Multiply each possible outcome by its probability then add