Topic 6: Samples and Populations/Making Inferences

A school surveys all 7th grade boys to determine what to sell in the school store.  This sample is _________.

• Biased
• Unbiased
• Representative

A student wants to know which type of pizza the students at his high school prefer. Which option would give a unbiased, representative sample:

• Asking all the students in the hot lunch line.
• Asking 10 random students from each homeroom.
• Asking every other student who gets off a school bus.
• Asking all the 10th graders.

I drew 10 names from a hat containing the names of every student that I teach, what type of sample have I taken?

• A random sample.

• A biased sample.

• A systematic sample.

• A voluntary response sample.

Find the mean of these numbers:
5, 11, 2, 12, 4, 2

• 4.1

• 6

• 4.5

• 4

Answer explanation

The mean of the given numbers is 6. It is calculated by summing all the numbers and dividing the sum by the total count of numbers. The correct choice is 6.

The number of people that called a doctor's office every hour are the following:

1, 2, 3, 3, 5, 5, 9

Find the Mean.

• 7

• 6

• 4

• 3

Answer explanation

The mean is calculated by summing all the numbers and dividing by the total count. In this case, (1+2+3+3+5+5+9)/7 = 4. Therefore, the correct choice is 4.

How do you calculate the Mean (average)?

• Finding the middle number

• adding all numbers up and dividing by how many numbers there are.

• Subtracting the greatest value from the least value number in the data set.

• Finding what number occurs the most.

What are the steps when finding the mean absolute deviation?

• 1. 1) Find the distance each value is from the mean. 2) Find the mean of the distances. 3) Find the mean of the data.

• 1) Find the mean of the distances. 2) Find the distance each value is from the mean. 3) Find the mean of the distances.

• 1) Find the mean of the data. 2) Find the distance each value is from the mean. 3) Find the mean of the distances.

What is the mean absolute deviation of the data: 15, 20, 25, 17, 18

• 4.5

• 2.8

• 4

• 3.8

What is the mean absolute deviation of the numbers:

10, 8, 5, 12, 20

• 3.4

• 4

• 11

• 5

Answer explanation

The mean absolute deviation is the average of the absolute differences between each number and the mean. The correct answer is 4, which gives the smallest average absolute difference.

The dot plots show how long it took students in Mr. Chauncey's two science classes to finish their science homework last night. Find the average to make an inference about the data.

• The 1st period mean is 35. The 2nd period mean is 38.75. On average, it took students in the 1st period class slightly longer to finish their homework than it did the students in the 2nd period class.

• The 1st period mean is 38.75. The 2nd period mean is 35. On average, it took students in the 1st period class slightly longer to finish their homework than it did the students in the 2nd period class.

• The 1st period mean is 35. The 2nd period mean is 38.75. On average, it took students in the 2nd period class slightly longer to finish their homework than it did the students in the 1st period class.

• The 1st period mean is 38.75. The 2nd period mean is 35. On average, it took students in the 2nd period class slightly longer to finish their homework than it did the students in the 1st period class.

Tags

CCSS.7.SP.B.4