5. Null hypothesis

Question 1

What four things does a set of scores tend to be? (Methods1 null hypothesis)

Answer 1

1) normally distributed
2) sample means normally distributed around population mean
3) differences between sample means normally distributed
4) sample means tend to be similar

Question 2

What is the central limit theorem? (Methods1 null hypothesis)

Answer 2

Sample means tend to be normally distributed around the population mean

Question 3

What is the probability of occurrence? (Methods1 null hypothesis)

Answer 3

Deviation from the mean, a sample mean which is very different from the population

Question 4

What does a null hypothesis suggest? (Methods1 null hypothesis)

Answer 4

Samples are from the same population and differences have arisen by chance

Question 5

What is a type 1 error? (Methods1 null hypothesis)

Answer 5

• Accepts the null hypothesis, when it is actually false
• Too lenient
• p=0.1

Question 6

What is a type 2 error? (Methods1 null hypothesis)

Answer 6

• Rejects the null hypothesis, when it is actually true
• Too stringent
• p=0.01

Question 7

What is a non-directional hypothesis? (Methods1 null hypothesis)

Answer 7

Samples will be different but no prediction of which direction

Question 8

What is a directional hypothesis? (Methods1 null hypothesis)

Answer 8

Samples will be different and the direction is predicted