Lecture #5 (Hypothesis Testing)

Question 1

What is a null hypothesis? (H0)

Answer 1

There is no pattern or trend - there is no difference - the accused is innocent

Question 2

What is a alternative hypothesis? (H1)

Answer 2

there is a pattern or trend - there is a difference - the accused is guilty

Question 3

Are H1 and H0 mutually exclusive?

Answer 3

Yes sir

Question 4

What percentage of significance is generally accepted?

Answer 4

95%

Question 5

Which is considered a more significant error? Type I or Type II?

Answer 5

Type I

Question 6

What is the difference between a one tailed and two tailed test?

Answer 6

A one tailed test measures both the left and right side of the distribution (5%) while the two tailed uses both sides (2.5% & 2.5%).

Question 7

What is a type I error?

Answer 7

A type I error is when the innocent is proven guilty

Question 8

What is a type II error?

Answer 8

A type II error is when the guilty is proven innocent

Question 9

How do you perform the Z-test?

Answer 9

z-calc = Difference between mean of the sample and the expected mean, divided by standard error of the mean

Question 10

When do you use a Z-test?

Answer 10

When you are making inference between a sample and it’s population. You are seeing if there is a difference between means of a sample and a population

Question 11

How do you perform a T-test?

Answer 11

tCalc = x̄− μ𝑜
————
𝑠√𝑛−1

Question 12

When do you use a T-test?

Answer 12

When you are comparing means of a sample to a population but (n<30)

Question 13

What is the difference between the Z-test and the T-test?

Answer 13

They both compare the mean of a sample to the mean of the population, however the T-test is for when (n<30) and the Z-test is for when (n>30)

Question 14

You want to compare the mean height of a random group of hockey players to the mean of the Canadian population. You sample 20 hockey players. What distribution should be used? Why?

Answer 14

T-test because (n<30)

Question 15

How do you find degrees of freedom in a T-test?

Answer 15

n-1

Question 16

How do you compare the portions of one sample if (n>30)?

Answer 16

Use the Z-test but include the expected proportion as a decimal in the formula
zCalc = x − n𝑃𝑜
——————
√(𝑛𝑃𝑜 (1−𝑃𝑜))

Question 17

What is the Z-crit value given a two-tailed test with an alpha value of 0.05?

Answer 17

Z-crit = +/- 1.96

Question 18

When do you use a paired test or related test?

Answer 18

When you are comparing two samples that are normally distributed and come from the same sample with known variances

Question 19

When do you use the independent test?

Answer 19

When you compare two separate samples with similar or different variances