AnswersCommon Core Math 7 - MA3107 CRInferences and Predictions

Inferences and Predictions Answers

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Two random samples were taken to determine how often people in a community listen to the local radio station each month. The first sample surveyed 15 people as they exited the bank on Main Street. The first sample found that the mean number of hours they listened to the radio each month was 20.The second sample surveyed every sixth person as they exited the only local grocery store until 100 people were surveyed. The second sample found that the mean number of hours they listened to the radio each month was 12.Which statements are true? Check all that apply.

A
The second sample is random.
B
The second sample is likely to be more representative of the population.
C
The first sample is likely to be more representative of the population.
D
The second sample will give a better representation because is it larger.
E
The first sample will give a better representation because it is smaller.
F
Community members are more likely to listen to the radio station an average of 12 hours a month than 20 hours a month.
3

The Hamden board of education wants to know how the community feels about building a new media center for the middle school. They called every tenth person on the registration list of 7,300 voters until they had called a total of 40 voters. Which of the following are true of the sample of 40 voters? Check all that apply.

A
The sample is not randomly chosen.
B
The sample should be larger to give more reliable information.
C
The sample size is too large to make inferences.
D
The sample size is too small to represent the population.
E
The sample size is too small and will show larger variation.
F
The sample is invalid because it randomly chooses voters.
G
The sample size is too small and can lead to false inferences.
4

When Jim surveyed 5 sixth-grade students at the community skating rink, he found that only 1 out of the 5 had completed the science project. He knows there are about 160 sixth-grade students in his community, so he infers that around 32 students have finished their science project. Is this a good inference?

A
No, Jim did not make a good inference because his sample is too small and may be biased because he only asked students that were at the rink.
B
No, Jim did not make a good inference because his sample is too small and 32 is not in the same proportion to the population as 1 to 5.
C
Yes, Jim made a good inference because 32 is the same proportion to the population as 1 to 5.
D
Yes, Jim made a good inference because most students at the rink were sixth graders.
6

At Brighton Middle School, Mr. Yule asked 50 randomly selected students from each grade level about their favorite subject, and 12 chose science. He used this data to draw the inference that about 25% of middle school students will indicate science is their favorite subject. If there are 200 students all together, did he make a reasonable inference?

A
No, Mr. Yule’s sample is biased and too small to be representative of the population.
B
Yes, Mr. Yule’s sample is small and biased, so it is representative of the population.
C
No, Mr. Yule’s percentage is too large. He should have used 6%.
D
Yes, Mr. Yule’s sample is random and representative of the population.
7

The drama club members at Millie’s middle school are selling tickets to the school play. Millie wants to determine the average number of tickets sold per member. First, she surveyed the club members in her homeroom, and then she surveyed every third member of the club in her physical education class from an alphabetical list of all members. Which sampling technique should produce a more representative sample?

A
Both samples should be exactly the same.
B
Neither sample will be representative.
C
The first sampling method, surveying club members in her homeroom, is the most representative.
D
The second sampling method, surveying club members in her physical education class, is the most representative.
8

The manager of a popular restaurant wants to know what types of vegetarian dishes people prefer to eat. Which sample would provide the most accurate data?

A
10 friends at a cookout
B
the first 30 people leaving the local hamburger stand
C
a random group of 40 people on the street
D
a random group of 5 people at a grocery store
9

The football and soccer teams at Juan’s middle school are selling movie tickets. He wants to determine the average number of tickets sold at the school. First, he surveyed eight random players on the football team. Then, he surveyed every third athlete on the football and soccer team. Which sampling technique should produce a more representative sample?

A
The first sampling method, surveying eight random football players, is the most representative.
B
Neither sample will be representative.
C
Both samples should be exactly the same.
D
The second sampling method, surveying the both teams, is the most representative.

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