T-tests Flashcards

1
Q

In a dependent sample t-test, what is the first step?

A

Find the research and the null hypothesis in words and symbols

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

In a dependent means t-test, what is step 2?

A

Determine the characteristics of the comparison distribution

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

What are the characteristics of a comparison distribution?

A

Mean
Standard deviation
Shape

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

What is the comparison distribution for a dependant means t-test?

A

Distribution of means of difference scores

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

What is the mean in a dependent means t-test?

A

Mew sub M = Mew

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

How to find standard deviation in dependent means t-test

A

S^2 = SS / N-1
S = square root of S^2
SM = S / square root of N

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

What is the shape in a dependent means t-test?

A

A t-distribution with N-1 degrees of freedom

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

What is step three of dependent means t-test?

A

Determine the cutoff score on the comparison distribution

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

How to find the cutoff score on the comparison distribution table

A

Go to the column of the df (N-1)
Go to the row of alpha (assume .05 if not given)
Find matching cutoff score

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

What is step four of dependent means t-test?

A

Determine the score of your sample on the comparison distribution of the means of difference scores
Find t

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

How to solve for t

A

t = M - mewM / SM

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

What is step 5 of dependent means t-test?

A

Determine whether or not to reject the null
- if the score of your sample falls further than the cutoff score then you reject the null.

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

Step one of single sample t-test

A

State the populations and a research and null hypothesis as words and symbols

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

Symbol version of population one

A

Mew 1

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

Mew 1 in words

A

Population one

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

Population two as symbols

A

Mew 2

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

Mew 2 as words

A

Population two

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

Null hypothesis for a single sample t-test

A

Mew 1 = Mew 2

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

What does the population 1 consist of in a single sample t-test?

A

The population being studied

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

What does the population 2 consist of in a single sample t-test

A

The general population

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

Research hypothesis in single sample t-test

A

Mew 1 does not equal Mew 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is step two in a single sample t-test?

A

Determine the characteristics of the comparison distribution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the characteristics of a comparison distribution in a single sample t-test?

A

Mean
Standard deviation
Shape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the comparison distribution for a single sample t-test?

A

Distribution of means

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
When you have 2 sets of means for each person in a dependent means t-test, what should you do?
Combine the means to make a difference score for each person
26
How to calculate a difference score for a dependent means t-test
Score 2 - score 1 (after - before) Mean of difference scores = MD
27
How to calculate deviation for a dependent means t-test
D - MD Difference score - the mean of difference scores
28
How to calculate squared deviation in a dependent means t-test
Square the deviation in the previous column SSD = sum of squares D
29
How to find SSD (Sum of Squares D)
Add together all of the squared deviations
30
What is the research hypothesis for a dependent means t-test?
Research shows an increase = Mew after - Mew before > 0 - difference scores are greater than 0
31
What is the null hypothesis for a dependent means t-test?
The mean of the population of difference scores = 0 - no difference - or an effect in the opposite direction of the research hypothesis
32
What is the mean symbol in a single sample t-test?
Mew sub M = Mew
33
Calculate standard deviation in a single sample t-test
USE SAMPLE VARIANCE WHEN POPULATION VARIANCE ISN’T GIVEN! Sigma sub M = sigma / square root of N OR SD^2 = SS / N OR S^2 = SS / N - 1 or SS / df
34
Formula for estimated population variance
S^2 = SS / N-1
35
Estimate of the population standard deviation
S = square root of S^2
36
Estimated standard deviation of the distribution of means
SM = S / square root of N
37
What is the shape of the comparison distribution in a single sample t-test?
T-distribution with N-1 df
38
T-distribution
When the df is higher, the distribution shape looks more normal When the df is lower, the distribution shape looks more heavy tailed
39
Step three of single sample t-test
Determine the cutoff sample score using a t table
40
Step four of single sample t-test
Determine where the sample score falls on the comparison distribution - goes on each side of the curve
41
How to find t for a single sample t-test
t = ( M - Mew sub M ) / SM
42
In a single sample t-test, which side of the curve do we put the cutoff score?
Both sides (one negative and one positive)
43
Step five of single sample t-test
Decide whether or not to reject the null
44
How do you know to reject the null in a single sample t-test?
If the sample score is different to the cut off score
45
What is the comparison distribution for a t-test for independent means?
A distribution of differences between means
46
How to calculate comparison distribution for a independent means t-test
Take the mean of the experimental groups distribution of means Take the mean of the control groups distribution of means Subtract the control group from experimental group to get difference between means
47
Three characteristics of a comparison distribution in independent means t-test
Mean Shape Standard deviation
48
Find the mean in an independent means t-test
Mew M1-M2 = 0
49
Find the shape of the comparison distribution for an independent means t-test
T-distribution with df total
50
How to calculate df total
df total = df1 + df2 - df1 = N1-1 - df2 = N2-1
51
What is the standard deviation for an independent means t-test
Standard deviation = Sdifference
52
Sdifference Independent means t-test
1. S1^2 = SS1 / N1-1 and S2^2 = SS2 / N2-1 2. S^2pooled = [df1 / df total (S1^2) ]+[df2 / df total (S2^2) ] 3. SM1^2 = S^2pooled / N1 and SM2^2 = S^2pooled / N2 4. S^2 difference = SM1^2 = SM2^2 5. S difference = square root of S^2 difference
53
If there are 10 volunteers and I randomly assign half of them to each group, what’s the N of each group? Independent means t-test Q
N1 = 5 N2 = 5
54
For each sample in an independent means t-test, what should I calculate?
The mean and the sum of squares for each
55
What is population one in an independent means t-test?
The experimental population/ group
56
What is population two in an independent means t-test?
The control population/ sample group
57
What is the research hypothesis in an independent means t-test?
Pop1 < Pop2 OR Pop1 > Pop 2
58
What is the null hypothesis in an independent means t-test?
The opposite to the research hypothesis
59
Step three of an independent means t-test
Find the cutoff score on the comparison distribution
60
How to find the cutoff score of the comparison distribution
One or two tailed test? df = ? Alpha = ? (assume .05 if not told)
61
Step four of an independent means t-test
Score of the sample on the comparison distribution
62
Score of the sample on the comparison distribution
t = [(M1 - M2) / Sdifference ] - 0
63
Step five of an independent means t-test
Decide whether to reject the null
64
How do you reject the null in an independent means t-test?
If the sample score is more extreme than the cutoff score
65
Effect size
The difference between the population means divided by the population’s standard deviation d = (mew1 - mew2) / sigma
66
Calculate estimated d
d = (mew1 - mew2) / Spooled
67
Effect size conventions
.20 = small .50 = medium .80 = large
68
Find power in an independent means t-test
Decide if it’s a one or two tailed test Find N overall (2 groups of 5 = 10) What is the effect size?