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STAT 350 – Fall 2008
Homework #8 – Solution
through Lecture #12
You can get pvalues that are more precise than what is possible using the ChiSquared Table in
the Appendix of your textbook in Excel using the function “ChiDist”.
For example, if your chi
square statistic is 30.54 and the degrees of freedom is 9, in Excel type “=ChiDist(30.54,9)” and
excel will return the pvalue.
Text Exercises
Chapter 8 problems #42, 44, 46
For each of the text problems, your work MUST show (i) the table of expected
counts, (ii) the
value of the ChiSquare statistic, (iii) the degrees of freedom for the test, and (iv) the
p
value of
the test.
8.42
Business
Engineering Social ScienceAgriculture TOTAL
0.4
0.3
0.2
0.1
1
48
36
24
12
120
52
38
21
9
120
(OE)
2
/E: 0.3333333330.111111111
0.375
0.75
1.569444
χ
2
= 1.569444, df = 41 = 3,
p
value = 0.666
Therefore we would not
reject the null hypothesis that the percentages for the 4 catageories
are 40%, 30%, 20% and 10%, respectively.
8.44
location
(i)
π
i
expected
frequencies
observed
counts
expected
counts
(OE)
2
/E
1
0.033333
4
6.666667 1.066667
2
0.066667
15
13.33333 0.208333
3
0.1
23
20
0.45
4
0.133333
25
26.66667 0.104167
5
0.166667
38
33.33333 0.653333
6
0.166667
31
33.33333 0.163333
7
0.133333
32
26.66667 1.066667
8
0.1
14
20
1.8
9
0.066667
10
13.33333 0.833333
10
0.033333
8
6.666667 0.266667
Sum
1
200
200
6.6125
χ
2
= 6.6125, df = 101 = 9,
p
value = 0.6774.
Therefore we would not
reject the null hypothesis that the true (longrun) proportion of
requests for location
i
is (5.5  
i
– 5.5)/30
Homework #8 – Solution
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This note was uploaded on 02/23/2009 for the course STAT 350 taught by Professor Staff during the Fall '08 term at Purdue University.
 Fall '08
 Staff
 PValues

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