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Chapter 9. The Basics of Experimentation and Testing for a Difference Between Means
Name:
Class:
Date:
From Kiess and Green’s
Statistical Concepts for the Behavioral Sciences , 4/e
Assignment 9.1
The purpose of this assignment is to help you to become more comfortable in recognizing
what each statistical symbol and formula in Chapter 9 represents. For each item in the
table below, either the term or the definition is given. Complete the table with the missing
information. For example, for the
betweensubjects design
, write the definition in the
appropriate column. It is best to complete this page without looking at your notes or
textbook. Once you have completed it, refer back to your notes and textbook to verify
you are correct.
Term
Definition
Betweensubjects design
Withinsubjects design
The probability of failing to find a statistically significant
difference when one is actually there
Obtaining subjects from among people who are accessible or
convenient to the researcher
Extraneous variables
The amount a sample mean differs from its population mean
Confound
Groups in which the subjects are not expected to differ in any
systematic or consistent way
Alternative hypothesis
Standard deviation of a theoretical sampling distribution of
12
X
X
−
Random assignment
Developed for measuring the effect of the independent
variable on the dependent variable
Statistically significant
difference
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View Full Document Chapter 9. The Basics of Experimentation and Testing for a Difference Between Means
Name:
Class:
Date:
From Kiess and Green’s
Statistical Concepts for the Behavioral Sciences, 4/e
Assignment 9.2
The data sets below provide scores obtained from two independent groups of subjects,
each group was given a different treatment condition,
X
1
and
X
2
, respectively. For each
data set, calculate a
t
test for independent groups. Then indicate the decisions you would
make for the statistical hypotheses. If you do find a statistically significant difference,
calculate the size of that effect.
Set A
Set B
Set C
X
1
X
2
X
1
X
2
X
1
X
2
43
39
15
13
540
400
50
37
14
14
460
415
61
35
11
15
600
440
60
38
13
13
520
430
58
40
12
15
430
420
49
36
13
460
Set D
Set E
Set F
X
1
X
2
X
1
X
2
X
1
X
2
91
101
100
98
3
5
92
105
101
105
5
4
95
102
102
110
4
3
96
107
98
96
3
5
98
99
98
5
3
Chapter 9. The Basics of Experimentation and Testing for a Difference Between Means
Answers for Assignment 9.2
Set A
X
1
X
2
43
39
50
37
61
35
60
38
58
40
49
36
Sum
321
225
n
6
6
X
53.5
37.5
SS
261.5
17.5
s
2
52.3
3.5
df
10
t
+5.25
Reject
H
0
Accept
H
1
2
η
=
.66
Set B
X
1
X
2
15
13
14
14
11
15
13
13
12
15
13
Sum
78
70
n
6
5
X
13
14
SS
10
4
s
2
2
1
df
9
t
–1.32
Fail to reject
H
0
Do not accept
H
1
No need to calculate
2
η
Set D
X
1
X
2
91
101
92
105
95
102
96
107
98
Sum
472
415
n
5
4
X
94.40
103.75
SS
33.20
22.75
s
2
8.3
7.58
df
7
t
–4.93
Reject
H
0
Accept
H
1
2
η
=
.86
Set C
X
1
X
2
540
400
460
415
600
440
520
430
430
420
460
Sum
2550
2565
n
5
6
X
510.0
427.5
SS
18000
2187.5
s
2
4500
437.5
df
9
t
+2.88
Reject
H
0
Accept
H
1
2
η
=
.48
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Set E
X
1
X
2
100
98
101
105
102
110
98
96
99
98
Sum
500
507
n
5
5
X
100.0
101.4
SS
10
139.2
s
2
2.5
34.8
df
8
t
–0.51
Fail to reject
H
0
Do not accept
H
1
No need to calculate
2
η
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This note was uploaded on 03/15/2010 for the course PSYCHOLOGY 100B taught by Professor Firstenberg,i. during the Winter '10 term at UCLA.
 Winter '10
 FIRSTENBERG,I.

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