Stats

Question 1

Normal distribution with a known variance, n < 30

Answer 1

Z statistic

Question 2

Normal distribution with a known variance, n>30

Answer 2

Z statistic

Question 3

Normal distribution with an unknown variance, n<30

Answer 3

t statistic

Question 4

Normal distribution with an unknown variance, n>30

Answer 4

t statistic* *you can use the z statistic here but t statistic is more conservative and therefore more preferred

Question 5

Nonnormal distribution with a known variance, n<30

Answer 5

not available

Question 6

Nonnormal distribution with a known variance, n>30

Answer 6

Z statistic

Question 7

Nonnormal distribution with an unknown variance, n<30

Answer 7

not available

Question 8

Nonnormal distribution with an unknown variance, n>30

Answer 8

t statistic* *you can use the z statistic here but t statistic is more conservative and therefore more preferred

Question 9

Type I Error

Answer 9

Type I Error is when you reject the null Hypothesis when it’s true

Question 10

Type II Error

Answer 10

Type II Error is when you fail to reject a false null Hypothesis

Question 11

Power of a test

Answer 11

Power of a test is the probability of correctly rejecting a false null hypothesis

Question 12

When level of significance is 10%, the Z values will be

Answer 12

For 2-tailed test: 1.65 For 1-tailed test: 1.28

Question 13

When level of significance is 5%, the Z values will be

Answer 13

For 2-tailed test: 1.96 For 1-tailed test: 1.65

Question 14

When level of significance is 1%, the Z values will be

Answer 14

For 2-tailed test: 2.576 For 1 tailed test: 2.33

Question 15

The chi-square test is used for

Answer 15

A chi-square statistic is used to test a hypothesis about the variance of a single population.

Question 16

When testing a hypothesis about the equality of variances of two normally distributed populations, you use

Answer 16

F-statistic

Question 17

Parametric tests

Answer 17

Parametric tests rely on assumptions regarding the distribution of the population and are specific to population parameters.

Question 18

Nonparametric tests

Answer 18

Nonparametric tests either do not consider a particular population parameter or have few assumptions about the population that is sampled. Nonparametric tests are used when there is concern about quantities other than the parameters of a distribution or when the assumptions of parametric tests can’t be supported. They are also used when the data are not suitable for parametric tests (e.g., ranked observations).

Question 19

decision for 2-tailed test

Answer 19

Reject H0 if: -(test statistic) < lower critical value

upper critical value < test statistic

Question 20

Decision for 1-tailed test

Answer 20