Unit Test — Unit test Answers

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The hourly wages earned by 20 employees are shown in the first box-and-whisker plot below. The person earning $15 per hour quits and is replaced with a person earning $8 per hour. The graph of the resulting salaries is shown in plot 2.Plot 1 Plot 2 How does the mean and median change from plot 1 to plot 2?

Question illustration
A
The mean and median remain the same.
B
The mean decreases, and the median remains the same.
C
The mean remains the same, and the median decreases.
D
The mean and median decrease.
2
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A manager of a grocery store wants to determine if consumers are spending more than the national average. The national average is $150.00 with a standard deviation of $30.20. The manager collects 40 random receipts and finds that the average is $160. Complete a hypothesis test with a significance level of 2.5% to determine if the average customer spends more in his store than the national average. Which of the following is a valid conclusion for the manager based on this test?

A
The customers spend more than the national average in his store.
B
The manager should decrease prices in his store.
C
The customers do not spend more than the national average in his store.
D
The customers in his store just come from a rich neighborhood.
3

The difference between an observational study and an experiment is that

A
in an observational study, only one group is studied, and in an experiment, two groups are studied.
B
in an observational study, the researchers do not control treatment, and in an experiment, they do.
C
in an experiment, cause-and-effect is analyzed, and in an observational study, it is not.
D
in an experiment, one group is studied over a short period of time, and in an observational study, the group is studied over a longer period of time.
4

The right isosceles triangle shown is rotated about line k with the base forming perpendicular to k. The perimeter of the triangle is 58 units.

Question illustration
A
a cone with a base radius of 17 units
B
a cone with a base radius of 34 units
C
a cylinder with a base radius of 17 units
D
a cylinder with a base radius of 34 units
5

In Juneau, Alaska, the 30-year annual snowfall average is 86.7 inches with a standard deviation of 40.4 inches. The last four years saw an average annual snowfall of 115.7 inches, 62.9 inches, 168.5 inches, and 135.7 inches. Hia performs a hypothesis test on this data to determine if the next 30-year norm will have a different average if the trend from the last four years continues. She uses a significance level of 5%. Which of the following is a conclusion that she may make?

A
The z-statistic is 1.44, so the null hypothesis cannot be rejected.
B
The z-statistic is 1.68, so the null hypothesis cannot be rejected.
C
The z-statistic is 1.85, so the null hypothesis should be rejected.
D
The z-statistic is 4.6, so the null hypothesis should be rejected.
6

Which statements are true? Select three options.

A
The population density for City B can be found using the ratio 48,592 : 26.
B
The population density for City D can be found using the ratio 258 : 196,429.
C
City A has the greatest population density of the four cities.
D
The population density of City B is greater than that of City C.
E
City D has the lowest population density of the four cities.
7

A convenience sample differs from a voluntary sample in that

A
a convenience sample is structured based on accessibility to the researcher, and a voluntary sample is based on participant interest.
B
convenience samples survey each participant once, and voluntary samples survey each participant numerous times.
C
convenience sampling is a method of random sampling, and a voluntary sample is not.
D
convenience sampling is not a probability-based method, and voluntary sampling is.
8

The graph below is used by company 2 to show the average monthly electric cost based on the electricity provider.How could the graph be redrawn so that the difference in monthly electric cost does not appear as great?

Question illustration
A
The scale on the y-axis could be changed to 0–150.
B
The scale on the y-axis could be changed to 100–120.
C
The interval on the y-axis could be changed to count by 1s.
D
The interval on the y-axis could be changed to count by 20s.
9

An area reserved for a parking lot is 80 feet long and 77 feet wide. The stalls of the lot are at 90° angles to two one-way aisles. Each aisle is 80 feet by 10 feet. The three areas set aside for the parking spaces are congruent rectangles.

Question illustration
A
10
B
30
C
35
D
40
10

The mean of a set of credit scores is and . Which statement must be true about z694?

Question illustration
A
z694 is within 1 standard deviation of the mean.
B
z694 is between 1 and 2 standard deviations of the mean.
C
z694 is between 2 and 3 standard deviations of the mean.
D
z694 is more than 3 standard deviations of the mean.
11

A solid right pyramid has a regular hexagonal base with an area of 5.2 cm2 and a height of h cm.

Question illustration
A
(5.2)h cm3
Option A
B
(5.2)h cm3
Option B
C
(5.2)h cm3
Option C
D
(5.2)h cm3
Option D
12

The mean test scores with standard deviations of four English classes are given below.ClassMeanStandard DeviationMrs. Jones891.9Mrs. Rijo821.4Mr. Phan733.4Mrs. Scott906.1Which statement is most likely to be true?

A
The scores of Mrs. Scott’s class are the closest to the class mean.
B
The scores of Mr. Phan’s class are the closest to the class mean.
C
The scores of Mrs. Jones’s class are the closest to the class mean.
D
The scores of Mrs. Rijo’s class are the closest to the class mean.
13

The diameter of the base of the cone measures 8 units. The height measures 6 units.

Question illustration
A
24π cubic units
B
32π cubic units
C
48π cubic units
D
64π cubic units
14

A solid oblique cone with a slant length of 17 units is placed inside an empty cylinder with a congruent base of radius 8 units and a height of 15 units.

Question illustration
A
320π cubic units
B
597π cubic units
C
640π cubic units
D
725π cubic units
15

Which three-dimensional figure has double the number of edges as faces?

A
rectangular prism
B
rectangular pyramid
C
triangular prism
D
triangular pyramid
16

A solid oblique pyramid has a regular pentagonal base. The base has an edge length of 2.16 ft and an area of 8 ft2. Angle ACB measures 30°.

Question illustration
A
5 ft3
B
9 ft3
C
14 ft3
D
19 ft3
17

Nikhil asked 120 randomly chosen moviegoers to watch a clip of an upcoming movie and choose the best title. The title "Everything” was chosen by 36 of the moviegoers as the preferred title.

A
between 4% and 10%
B
between 7% and 30%
C
between 23% and 37%
D
between 29% and 43%
18

A prior study determined the point estimate of the population proportion as 23% ( = 0.23). The analysts want to conduct a second survey about the same topic that has a margin of error, E, of 17% and a confidence level of 99% (z*-score of 2.58).

Question illustration
A
3
B
7
C
12
D
41
19

Every possible cross section of a three-dimensional figure is a circle. What is the figure?

A
cone
B
cylinder
C
circle
D
sphere
20

The base of a solid right pyramid is a regular hexagon with a radius of 2x units and an apothem of units.

Question illustration
A
units2
Option A
B
units2
Option B
C
units2
Option C
D
units2
Option D

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