Null Hypothesis Testing Flashcards

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1
Q

Name the 2 hypotheses that Null Hypothesis Testing involves.

A

Null Hypothesis

Alternative Hypothesis

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2
Q

H0 = _____________

A

null hypothesis

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3
Q

H1= ________

A

alternative hypothesis

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4
Q

What is the null hypothesis?

A

Statement about the independence or equality in populations. Essentially saying nothing is happening, no effect.

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5
Q

What is the alternative hypothesis?

A

Statement about the presence of important differences or associations in populations. Essentially saying there is some kind of effect.

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6
Q

What hypothesis do we always favour?

A

The null hypothesis.

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7
Q
What hypothesis is this?:
"there is no difference between results of men and women in the class test"
A

Null Hypothesis

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8
Q
What hypothesis is this?:
"There is a difference between results of men and women in class test"
A

Alternative Hypothesis

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9
Q

We calculate the _____ that the difference between men and women’s scores was by chance.

A

Probability

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10
Q

What is probability?

A

the likelihood or chance that something will happen.

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11
Q

What is the probability equation?

A

P = number of actual outcomes/ number of possible oustcomes.

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12
Q

How do we decide if an observed difference is large enough to allow us to reject the null hypothesis?

A

If p = < .05

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13
Q

If the difference occurred by chance less than 1 in ___ e.g. 0.05 or 5%

A

20

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14
Q

What does the 5% chance correspond to?

A

The 5% of scores outwith the 95% - 2.5% on each side of the normal distribution

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15
Q

If P = > 0.05 you ____ the NH.

A

accept

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16
Q

If p= >0.05 is it significant?

A

no

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17
Q

If p = <0.05 you _____ the NH

A

reject

and accept the AH!

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18
Q

If p = <0.05 is it significant?

A

YES

19
Q

If p is low then the null must….

A

GO

20
Q

non-significant results don’t mean _____ results.

A

insignificant

21
Q

What is an Effect Size?

A

Effect Size tells you about the magnitude of an effect rather than simply whether it is significant.

22
Q

Effect sizes don’t depend on _______

A

sample size

23
Q

Effect sizes are ____ across studies.

A

Standardised

24
Q

effect sizes means you can _____ across studies.

A

compare

25
Q

Null hypothesis testing is based on _____ not certainties.

A

probabilities

26
Q

What is a Type I error?

A

Rejecting the NH when you shouldn’t have.

Aka. Saying something is significant when it’s not.

27
Q

For controlling a type I error what is the alpha usually set at?

A

The alpha is set at .05.

28
Q

What does setting the alpha at .05% do?

A

this means there is a 5% chance of making a type 1 error.

29
Q

how can you decrease your chances of making a type I error even more?

A

Make the alpha more stringent e.g. .01

30
Q

What’s the problem with making alpha more stringent?

A

It increases the chance of making a type II error.

31
Q

What is a Type II error?

A

Accepting the NH when you shouldn’t have.

Aka. saying there is no effect when there one!

32
Q

What is the probability of making a Type I error called?

A

Alpha

33
Q

What is the probability of making a Type II error called?

A

Beta

34
Q

Name the 3 factors Beta is influenced by?

A
  1. Alpha - the more stringent the alpha, the more difficult it gets to reject the NH.
  2. sample size - a larger sample size means greater power and reduces the likelihood of a Type II error/beta
  3. Effect size- a larger effect size means greater power and reduces the likelihood of a Type II error/beta
35
Q

What is statistical power?

A

A statistical test’s ability to detect an effect if there is one.

36
Q

Power is defined as 1 - _____

A

beta

37
Q

power is measured on a _ - _ scale.

A

0 to 1

38
Q

The closer to 1 the _____ the power.

A

greater

39
Q

The close beta is to 1 the ____ the chance of making a type II error.

A

greater

40
Q

Beta is measured on a __-__ scale.

A

0 to 1

41
Q

We want beta to be very ____

A

small.

42
Q

What is power usually set at?

A

0.8

43
Q

What does power being set at 0.8 mean?

A

Your study has an 80% chance of correctly rejecting the null hypothesis. And has 20% chance of making a type II error.

44
Q

What is alpha and power set at in G power?

A
  1. 05

0. 80