In: Math
Elwin Osbourne, CIO at GFS, Inc., suspects that at least 25% of e-mail messages sent by GFS employees are not business related. A random sample of 300 e-mail messages was selected to test this hypothesis at the 0.01 level of significance. Fifty-four of the messages were not business related. The appropriate decision is _______.
increase the sample size |
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gather more data |
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reject the null hypothesis |
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fail to reject the null hypothesis |
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maintain status quo |
Null hypothesis
Alternative hypothesis
We have for given example,
Population proportion value is =0.25
x=54
n=300
Level of significance = 0.01
Estimate for sample proportion =54/300=0.18
Z test statistic formula for proportion
=-2.8
P value =0.0024.................by using Z table or Excel =NORMSDIST(-2.8)
P value < 0.01
reject the null hypothesis |