Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Statistics > Power Analysis > Flashcards

Power Analysis Flashcards

1
Q

A statistical tests power is the probability that it will…

A

Avoid Type 2 error/correctly pick up on an effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

This hypothesis states that the difference between the two variables is zero

A

Null

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

One motivation for conducting a study is to provide evidence that the hypothesis is true. We do this by showing…

A

The null hypothesis is unlikely

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

A Type 1 error is where

A

False positive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

A Type 2 error is a

A

False negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

“Rejection of the null, when it is in fact true”

A

Type 1 error

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is an effect?

A

What was found

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is effect size

A

Measures strength of result - magnitude-based

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Difference between EFFECT SIZE and SIGNIFICANCE?

A

Effect size does not depend on sample size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The p value indicates if what was found is g..

A

Generalisable to a population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Effect size does not depend on

A

Sample size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

If we find a non-significant p-value despite a large effect, this is likely because

A

Small sample

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

A prospective power analysis shows us that a certain ________ are needed to yield a significant result

A

Number of pps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Sufficient power to find statistical significance minimises

A

Chance findings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

A power analysis is where one of several _______________ can be calculated given others

A

Statistical parameters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

There are ___ parameters involved in a power analysis

A

4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

4 parameters involved in a power analysis

A

(i) Alpha
(ii) Power
(iii) N
(iv) Effect size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Coefficient alpha is the p…

A

Probability of finding significance where there is none - Making a Type 1 Error

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Coefficient alpha is usually set to

A

.05

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Power is usually set to

A

.80

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Power is the probability of finding

A

True significance

22
Q

Power is the probability of avoiding

A

A type 2 error

23
Q

Power analysis

The parameter usually solved for is…

A

N

24
Q

Expected effect size may be ascertained from… (4)

A
  1. Pilot study
  2. Findings from similar study
  3. Field defined ‘meaningful effect’
  4. Educated guess
25
Q

Alpha is usually set to ___ and power is usually set to ___

A

.05

.80

26
Q

When trying to ascertain effect size, if there are no similar studies…

A

Start with pilot study

27
Q

There are FOUR TYPES OF POWER ANALYSIS

A

Priori
Post-hoc
Criterion
Sensitivity

28
Q

For a priori, you’d compute ___. The rest is given

A

Sample size (N)

29
Q

For a post-hoc, you’d compute ____. The rest is given

A

Power

30
Q

For a criterion, you’d compute ___. The rest is given

A

Alpha

31
Q

Which type of power analysis is USUALLY DONE

A

Priori

32
Q

A 72% power indicates that you have a 72% chance of

A

Avoiding making a Type 2 error/Picking up on an effect

33
Q

Power is increased when a researcher increases

A

Sample size/Effect Levels/Significance Levels

34
Q

_______ is increased when a researcher increases sample size/effect levels/significance levels

A

Power

35
Q

How to calculate effect size

A

M1 + M2 / SD (collective)

36
Q

A power analysis is where

A

One of several statistical parameters can be calculated given others

37
Q

Reporting a prospective priori order

A
  1. Pps
  2. Effect size
  3. Alpha
  4. Power
38
Q

Reporting a sensitivity order

A
  1. Pps
  2. Effect size
  3. Alpha
  4. Power
39
Q

Reporting a post-hoc

A
  1. Effect size
  2. Pps
  3. Alpha
  4. Only achieved 73% power
40
Q

How do you begin reporting a post-hoc

A

The effect size for this study was calculated as

41
Q

How do you begin reporting a retrospective priori

A

The effect size for this study was calculated as

42
Q

Statistical power depends on (3)

A
  1. Effect size
  2. Sample size
  3. Precision of measures
43
Q

Why does statistical power depend on precision of measures?

A

More reliable measures = smaller SE’s/more precise variable estimates

44
Q

Effect size

The ______ the better

A

Larger

45
Q

Sample size

Larger sample size =

A

Smaller SE’s

46
Q

Error bars

Small samples will have

A

Large error bars

47
Q

Error bars

Easier to estimate when

A

Error bars are smaller

48
Q

Large error bars = _____ sample size

A

Small

49
Q

Prospective power analysis

We don’t want to recruit too many pps

A

As this could result in significant result regardless of effect size

50
Q

Other than a Priori, you could calculate required sample size

A

Using Cohen’s table

51
Q

Why does sample size affect power

A

Larger = smaller SE’s

Small, non-overlapping error bars

Statistics (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions