PRETEST 3 for Test 3.
Test 3 will be on Monday April 28. Questions and answers.
Solutions
will be posted with corresponding homework solutions.
I.
Multiple choice/short answer questions: Study all Prequiz questions (with emphasis on Prequizzes 5 and 6 and
all Quiz Questions (with emphasis on Quizzes 5 and 6) plus these:
I1.
Which of the following will increase the width of a confidence interval? (a) Decrease the confidence value from
99% to 95% (b) Increase the mean (c) Increase the sample size
(d) Decrease the sample size
I2.
The probability that a random variable having the
t
distribution with 4 degrees of freedom is
less than
t
0.01
equals
(a) 0.99
(b) 0.01
(c) 0.98
(d) 0.02
I3. We test H
0
:
μ
=0.0 vs. H
1
:
μ
<0.0 at the
α
=0.01 level. (n =100). The rejection region is
(a) Z <
2.33
(b) Z >
2.33
(c) Z <
2.33
(d) {Z >2.33} = {Z >
2.33 or Z<
2.33}
I4 and I5.
A researcher tests H
0
:
μ
=10 vs. H
1
:
μ≠
10 at the 0.05 level using a sample of 100.
The standard
deviation is known to equal 20. He computes the probability of this type II error (
β
) of his
test to be 0.50 for
μ
=14 and for
μ
=6.
I4.
If
μ
=15
the probability he will not reject Ho at the 0.05 level
is greater than 0.5.
TRUE
FALSE
I5.
Suppose
μ
=10.
If the investigator rejects Ho, he is wrong.
TRUE
FALSE
I6.
We test H
o
:
μ
=48mm vs. H
a
:
μ≠
48mm at the
α
=0.05 level. The standard
deviation is unknown
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 Fall '03
 Mendell
 Normal Distribution, Null hypothesis, Statistical hypothesis testing

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