1.
From past records
it is known that the average life of a battery used in a digital clock is 305
days. The battery life is normally distributed. The battery was recently
modified to last longer. A sample of 20 of the modified batteries was
tested. It was discovered that the mean life was 311 days and the sample
standard deviation was 12 days. We want to test at the 0.05 level of
significance whether the modification increases the life of the battery. What
is our decision rule?

A:
Do not reject
the null hypothesis if computed t is 1.96 or greater
B:
None of the
above
C:
Do not reject
the null hypothesis if computed t is 1.729 or greater
D:
Reject the null
hypothesis if computed t is 2.086 or greater

2.
A manufacturer
wants to increase the absorption capacity of a sponge. Based on past data,
the average sponge could absorb 3.5 ounces. After the redesign, the absorption
amounts of a sample of sponges were (in ounces): 4.1, 3.7, 3.3, 3.5, 3.8, 3.9,
3.6, 3.8, 4.0, and 3.9. What is the decision rule at the 0.01 level of
significance to test if the new design increased the absorption amount of the
sponge?

A:
Do not reject
null hypothesis if computed t is less than 2.580
B:
Do not reject
null hypothesis if computed t is less than 2.821
C:
Reject null
hypothesis if computed z is 1.96 or larger
D:
Reject null
hypothesis if computed t is less than 2.764

3.
If the alternate
hypothesis states that
m
does not equal 4,000, what is the rejection region for the hypothesis test?

A:
Both tails
B:
Lower or left
tail
C:
Upper or right
tail
D:
Center

4.
If the 1% level of
significance is used and the computed value of z is +6.00, what is our
decision?

A:
Do not reject H_{0
}
B:
Reject H_{0
}
C:
Reject H_{1
}
D:
None of the
above

5.
A manufacturer of
stereo equipment introduces new models in the fall. Retail dealers are
surveyed immediately after the Christmas selling season regarding their stock
on hand of each piece of equipment. It has been discovered that unless 40% of
the new equipment ordered by the retailers in the fall had been sold by
Christmas, immediate production cutbacks are needed. The manufacturer has
found that contacting all of the dealers after Christmas by mail is
frustrating as many of them never respond. This year 80 dealers were selected
at random and telephoned regarding a new receiver. It was discovered that 38%
of those receivers had been sold. Since 38% is less than 40%, does this mean
that immediate production cutbacks are needed or can this difference of 2
percentage points be attributed to sampling? Test at the 0.05 level.
Computed z = –0.37.

A:
Cut back
production
B:
Do not cut back
production
C:
Cannot determine
based on information given
D:
None of the
above

6.
If 20 out of 50
students sampled live in a college dormitory, what is the estimated proportion
of students at the University living in a dormitory?

A:
0.20
B:
0.40
C:
0.50
D:
0.60

7.
Use the following to answer questions 711:
The
average cost of tuition, room and board at small private liberal arts colleges
is reported to be $8,500 per term, but a financial administrator believes that
the average cost is higher. A study conducted using 150 small liberal arts
colleges showed that the average cost per term is $8,745 with a standard
deviation of $1,200. Let a = 0.05.
What is the
null and alternative hypotheses for this study?

A:
Null:
m
£
$9,000; alternative:
m
> $9,000
B:
Null:
m
³
$9,000; alternative:
m
< $9,000
C:
Null:
m
£
$8,500; alternative:
m
> $8,500
D:
Null:
m
³
$8,500; alternative:
m
< $8,500

8.
What is the
critical zvalue for this test?

A:
+ 1.96
B:
– 1.96
C:
+ 1.65
D:
– 1.65

9.
What is the test
statistic for this test?

A:
±2.50
B:
0.204
C:
2.50
D:
+2.50

10.
What is the
pvalue for this test?

A:
0.0062
B:
0.0124
C:
0.0500
D:
0.4938

11.
Based on the
computed test statistic or pvalue, what is our decision about the average
cost?

A:
Equal to $8,500
B:
Greater than
$8,500
C:
Less than $8,500
D:
Not equal to
$8,500

12.
Use the following to answer questions 1215:
It
is claimed that in a bushel of peaches less than ten percent are defective. A
sample of 400 peaches is examined and 50 are found to be defective.
What is the
null hypothesis?

A:
p
¹
0.10
B:
p
³
0.10
C:
p
£
0.10
D:
p
< 0.10

13.
What is the
alternate hypothesis for a onesided test?

A:
p
¹
0.10
B:
p
< 0.10
C:
p
£
0.10
D:
p
= 0.10

14.
What is the zstatistic?

A:
0.025
B:
0.278
C:
–1.65
D:
1.67

15.
If
a
= 0.025, what will be the decision?

A:
Fail to reject
the null and conclude the defects are not greater than 10%
B:
Reject the null
and conclude the defects are not greater than 10%
C:
Reject the null
and conclude the defects are greater than 10%
D:
Fail to reject
the null and conclude the defects are not less than 10%
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