STAT 4: Introducing Hypothesis Testing

Question 1

What is the function for the inverse cumulative density of the binomial distribution?

Answer 1

qbinom (q, size, prob)

• q = a certain variable
• size = number of trials
• p = probability of success

Question 2

What is the p-value?

Answer 2

• the probability of getting a result that extreme or more assuming a null hypothesis is true

Question 3

What is a type I error?

Answer 3

• known as false positive
• occurs when the null hypothesis is true but you reject it

Question 4

What is a type II error?

Answer 4

• known as a false negative
• when you fail to reject the null hypothesis even though it is not true

Question 5

Explain what is meant by the statistical power of a test

Answer 5

• the statistical power of a test is the probability of correctly rejecting the null hypothesis

Question 6

How do you calculate statistical power?

Answer 6

1 - ß

• beta = overlap with fair test

Question 7

What type of dispersion and difference between peaks will result in the most statistically powerful experiment?

Answer 7

• low dispersion
• high difference between peaks

Question 8

What does alpha represent in a hypothesis test?

Answer 8

• significance level
• the proportion of false positives if the null hypothesis is true

Question 9

What affects power?

Answer 9

• effect size
• dispersion + peak difference
• n: number of trials

Question 10

Define beta

Answer 10

• the probability of a type II error
• the probability of accepting the null hypothesis when it is false