Unit Test — Unit test Answers

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A scientist is studying tulips and daffodils. The scientist estimates that there are 150 tulips in the population of 600 tulips and daffodils. He chooses flowers from random parts of the garden to study. Which best explains how he can choose a random sample of flowers to represent the population?

A
He can choose 50 flowers.
B
He can choose 25 tulips and 25 daffodils.
C
He can choose 15 tulips and 60 daffodils.
D
He can choose 10 tulips and 30 daffodils.
2
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Liliana wants to start a seventh-grade computer club at Hamden Middle School. She surveyed 20 seventh-grade students at the town park. She asked each student how many hours they spend on their computers each week. She obtained the following results.8, 15, 0, 11, 12, 13, 16, 13, 0, 4, 17, 14, 30, 13, 5, 12, 1, 13, 12, 21What is the ratio of the total number of students who used their computers to the total number of students surveyed?

A
or
Option A
B
or
Option B
C
or
Option C
D
or
Option D
3

Biologists are studying tropical plants to determine how far north each type of plant can survive. What is the population?

A
biologists
B
tropical plants
C
biologists participating in the research
D
the tropical plants that were moved farther north
4

The number of text messages that Reza sent each day so far in this billing cycle is shown on the dot plot.

Question illustration
A
The data is symmetric and shows that he typically sent about 6 to 8 text messages per day.
B
The data is symmetric and shows that he sent 11 or 12 texts with the same frequency that he sent 1 or 2 texts.
C
The data is skewed and shows that he typically sent about 6 to 8 text messages per day.
D
The data is skewed and shows that he sent 11 or 12 texts with the same frequency that he sent 1 or 2 texts.
5

Alejandro wants to determine the average shoe size of all of the male students in his school. Which sample is likely to yield the most biased results?

A
every tenth boy on the school’s phone list
B
every member of the boys’ basketball team
C
every boy in a randomly selected ninth-, tenth-, eleventh-, and twelfth-grade gym class
D
every fifth boy who walks through the front doors of the school in the morning
6

When Henry surveyed 45 seventh-grade students at random in the school cafeteria, he found that 3 out of 15 liked reggae music. Using proportional reasoning, about how many of the 180 seventh-grade students in his school like reggae?

A
About 12 seventh-grade students like reggae music.
B
About 36 seventh-grade students like reggae music.
C
About 60 seventh-grade students like reggae music.
D
About 108 seventh-grade students like reggae music.
7

A researcher wants to develop a product for families who have small children. He needs to determine if there is a nationwide interest in a toy that will help children describe their emotions. He asks only a sample of the population to complete his survey. What should be true of the sample so that the results of the survey can be used to predict the results of surveying the population?

A
The size of the sample should be the same size as the population.
B
The families included in the sample should represent the families in the population.
C
The families included in the sample cannot be included in the population.
D
The size of the sample should be larger than the size of the population.
8

Which best describes a random sample?

A
a sample in which the elements are chosen by chance
B
a sample in which the chosen elements are predetermined
C
a sample in which each element of the population is chosen
D
a sample in which the chosen elements are removed from the population once they are chosen
10

Myra polled twenty-five students in her class to determine the number of movies the students attended at the theater this year. The results are in the table. She decided to find the mean of a sample using Row 1 and Row 5.Number of Movies AttendedRow 165286Row 220452Row 334301Row 452633Row 523224What is the mean of her sample?

A
2
B
4
C
6
D
8
11

To conduct a survey about the type of phone service most people in Greenville prefer, 10 different blocks in the neighborhood are chosen. On these 10 blocks, 10 houses are selected at random, and then each resident of each of those houses is interviewed. This type of sampling method is

A
simple random sampling.
B
stratified sampling.
C
systematic random sampling.
D
cluster sampling.
12

Monique manages wildlife samples for Ducks Unlimited. Two samples of duck populations at a migratory site are shown in the table below. Which statement about the samples is true?Duck Pond SamplesSample 1Sample 2Mallard17Mallard21Wood Duck8Wood Duck7Green Wing Teal10Green Wing Teal8American Widgeon5American Widgeon6

A
Monique can use both samples to find the mean frequency of each duck.
B
Monique should take another sample because there is too much variability in the two samples.
C
Monique should use only the first sample to find the mean frequency of each duck.
D
Monique should use only the second sample to find the mean frequency of each duck.
13

Which statement illustrates a simulation that could be used to generate samples of people on a game show selecting either door A, door B, or door C?

A
Flipping a coin and getting heads for door A or tails for door C.
B
Rolling a die; 1 or 2 represents door A, 3 or 4 represents door B, and 5 or 6 represents door C.
C
Creating a spinner divided into 4 equal parts. Label two parts door A, one part door B, and the third part door C.
D
Go to the game show and collect data for a month on which doors people chose.
14

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.
15

School newspaper staff went to three different sports games to survey students on their favorite sport, and the results are shown in the table below. Are these samples biased? Why or why not?Favorite Sport SurveySample 1Sample 2Sample 3Basketball23Basketball1Basketball1Football2Football24Football2Volleyball0Volleyball0Volleyball22

A
These samples are not biased because students like different sports and the samples reflect the different opinions.
B
These samples are biased because the newspaper staff went to a basketball game, football game, and volleyball match to interview the students.
C
These samples are not biased because each has a total of 25 students, which makes them equal.
D
These samples are biased because 0 should never appear in a sample as it is not possible.
16

Melanie asked 15 random seventh-grade students how many soccer games they attended this school year. The number of games attended by each student is listed below.2, 3, 6, 4, 7, 0, 4, 5, 0, 1, 2, 3, 2, 1, 4What is the ratio of the total number of surveyed students who attended soccer games to the total number of students surveyed?

A
StartFraction 2 over 15 EndFraction
Option A
B
StartFraction 2 over 13 EndFraction
Option B
C
StartFraction 13 over 15 EndFraction
Option C
D
StartFraction 13 over 2 EndFraction
Option D
17

A nutritionist wants to know how the taste of artificial sweeteners impacts food choices of diabetic patients. From which group would it be best to take a sample?

A
all patients
B
both type 1 and type 2 diabetic patients
C
patients who do not eat any artificial sweeteners
D
patients who eat mostly artificially sweetened foods
18

Scientists are studying hurricanes to determine the number of hurricanes in the past 50 years that have caused greater than $1 million in damages. Which best describes the population?

A
hurricanes
B
hurricanes that caused greater than $1 million in damages
C
scientists
D
scientists participating in the research
19

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.
20

A random sample of people is chosen to participate in a survey. For the survey results to be considered valid, which must be true of the random sample?

A
The sample must be the same size as the population.
B
The sample must represent the target population.
C
The sample must be biased.
D
The sample must be a group separate from the population.

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