Lesson 13: Practice Problems

Problem 1

Here is data that shows student’s scores for 10 rounds of a video game.

  • 130

  • 150

  • 120

  • 170

  • 130

  • 120

  • 160

  • 160

  • 190

  • 140

What is the median score?

  1. 125

  2. 145

  3. 147

  4. 150

Problem 2

When he sorts the class’s scores on the last test, the teacher notices that exactly 12 students scored better than Clare and exactly 12 students scored worse than Clare. Does this mean that Clare’s score on the test is the median? Explain your reasoning.

Problem 3

Match each dot plot with its median.

median

  1. 6

  2. 12

  3. 13

  4. 15

dot plot

  1. A dot plot with one dot at 1, 2, 7, 9. Two dots at 5, 6, 7.
  2. A dot plot with one dot at 17-29, two dots at 10-11, and three dots at 15.
  3. A dot plot with one dot at 5, 6, 9, 13-14. Two dots at 11 and three dots at 15.
  4. A dot plot with one dot at 14, two dots at 8, 10, 11, and three dots at 16.

Problem 4

Invent a data set with five numbers that has a mean of 10 and a median of 12.

Problem 5 From Unit 8 Lesson 10

Ten sixth-grade students reported the hours of sleep they get on nights before a school day. Their responses are recorded in the dot plot.

A dot plot for "hours of sleep". The numbers 5 through 12 are indicated. The data are as follows: 5 hours, 1 dot; 6 hours, 1 dot; 7 hours, 3 dots; 8 hours, 3 dots; 9 hours, 2 dots; 10 hours, 0 dots; 11 hours, 0 dots; 12 hours, 0 dots.

Looking at the dot plot, Lin estimated the mean number of hours of sleep to be 8.5 hours. Noah’s estimate was 7.5 hours. Diego’s estimate was 6.5 hours.

Which estimate do you think is best? Explain how you know.

Problem 6 From Unit 8 Lesson 8

In one study of wild bears, researchers measured the weights, in pounds, of 143 wild bears that ranged in age from newborn to 15 years old. The data were used to make this histogram.

A histogram. The horizontal axis is labeled "weight in pounds" and the numbers 0 through 550, in increments of 50, are indicated. On the vertical axis, the numbers 0 through 40, in increments of 5, are indicated. There are also tick marks midway between. The approximate data for the bars are as follows: From 0 up to 50 pounds, 6 bears From 50 up to 100 pounds, 18 bears From 100 up to 150 pounds, 40 bears From 150 up to 200 pounds, 28 bears From 200 up to 250 pounds, 14 bears From 250 up to 300 pounds, 7 bears From 300 up to 350 pounds, 11 bears From 350 up to 400 pounds, 10 bears From 400 up to 450 pounds, 6 bears From 450 up to 500 pounds, 2 bears From 500 up to 550 pounds, 1 bear

  1. What can you say about the heaviest bear in this group?

  2. What is a typical weight for the bears in this group?

  3. Do more than half of the bears in this group weigh less than 250 pounds?

  4. If weight is related to age, with older bears tending to have greater body weights, would you say that there were more old bears or more young bears in the group? Explain your reasoning.