POLS 203
FALL 2006
PRACTICE PROBLEMS 2
Please note that in the exam you will be asked to show all the steps in answering the
question and at the end, interpret the results in a couple of sentences.
1.
A random sample of n=25 from a normally distributed population with σ=7 yields a sample
mean x=67.3. What is the 99% confidence interval for μ?
(63.688 to 70.912)
2.
We want to test the hypothesis that the mean of a population is μ=46. We draw a sample size
of n = 100 and obtain a sample mean x=51. We also have the information, population
variance=400.Compute the relevant test to test this hypothesis, showing all the necessary
steps. At which level of significance are you able to reject H
0
?
(z=2.5, reject at .05 level, fail to reject at .01 level)
3.
An auditor wants to test a company's claim that average accounts receivable could equal the
$375 stated on the balance sheet. The population standard deviation is $100.00. A sample
mean from 49 accounts was $400.00. (α=.05 significance level).
(t=1.75, fail to reject Ho)
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 Fall '07
 Kaynak
 Statistics, Standard Deviation, $375, $100.00

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