Part A: Random Assignment Throughout the quarter, we have claimed that random as
ID: 3449752 • Letter: P
Question
Part A:
Random Assignment
Throughout the quarter, we have claimed that random assignment will serve to create equivalent groups. This question asks you to think about how random assignment actually works with a small group of participants.
Use the data in the table below. You are welcome to copy and paste the numbers into an Excel spreadsheet.
This table describes 20 participants who differ on a number of variables. If you randomly assigned them to either an "Experimental" condition or a "Control" condition, would the two groups, on average, be equal?
Start at the top of the list. Flip a fair coin for each participant. If the coin lands on heads, assign that participant to the Experimental Condition. If the coin lands on tails, assign that participant to the Control Condition.
1. List the participant numbers that are in each condition.
2. What is the sample size of each group?
3. Calculate and report the means and standard deviations of Age, IQ and Self-esteem for both of the groups.
You are welcome to use Excel to calculate the means and standard deviations. Use the formulas =average and =stdev
4. Think about this:
Do the groups seem similar? Did random assignment result in the pesky individual differences being equally placed in the two groups? For these participants, Age has a very small range - your two groups are likely to be very similar. On the other hand, IQ has a very large range - your two groups might be quite different.
Explanation / Answer
exp
1
2
3
control
1
2
3
2
19
73
48
1
19
145
42
3
21
86
30
4
27
108
36
5
18
85
38
9
23
93
40
6
24
141
42
10
21
103
36
7
22
91
28
13
26
94
43
8
25
100
39
14
25
114
35
11
28
93
45
15
24
78
40
12
21
107
44
17
25
119
42
16
25
104
45
19
21
136
38
18
27
81
41
20
97
97
42
2- Sample size for experimental group is 11 and for control group is 9
3- Average for experimental group is 29.72 for age, 96.18 for IQ and 40.18 for self esteem and for control group it is 23.44 for age, 110 for IQ and 39.11 for self esteem.
4- Although range differs for age and IQ but there are no pesky individual differences. Yes differences occur in two groups but these differences are not very big to cause trouble and we can say that random assignment of groups does not cause much trouble although it is regarded good with large groups but it works fine with small groups too.
exp
1
2
3
control
1
2
3
2
19
73
48
1
19
145
42
3
21
86
30
4
27
108
36
5
18
85
38
9
23
93
40
6
24
141
42
10
21
103
36
7
22
91
28
13
26
94
43
8
25
100
39
14
25
114
35
11
28
93
45
15
24
78
40
12
21
107
44
17
25
119
42
16
25
104
45
19
21
136
38
18
27
81
41
20
97
97
42
2- Sample size for experimental group is 11 and for control group is 9
3- Average for experimental group is 29.72 for age, 96.18 for IQ and 40.18 for self esteem and for control group it is 23.44 for age, 110 for IQ and 39.11 for self esteem.
4- Although range differs for age and IQ but there are no pesky individual differences. Yes differences occur in two groups but these differences are not very big to cause trouble and we can say that random assignment of groups does not cause much trouble although it is regarded good with large groups but it works fine with small groups too.