Unit 8, Lesson 11
Estimating Population Measures of Center
Accelerated 6
Practice
Problem 1
Han and Priya want to know the mean height of the 30 students in their dance class. They each select a random sample of 5 students.
- The mean height for Han’s sample is 59 inches.
- The mean height for Priya’s sample is 61 inches.
Does it surprise you that the two sample means are different? Are the population means different? Explain your reasoning.
Problem 2
A video game developer wants to know how long it takes people to finish playing their new game. They surveyed a random sample of 13 players and asked how long it took them (in minutes).
- 1,235
- 952
- 457
- 1,486
- 1,759
- 1,148
- 548
- 1,037
- 1,864
- 1,245
- 976
- 866
- 1,431
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Estimate the median time it will take all players to finish this game.
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Find the interquartile range for this sample.
Problem 3
A random sample of 15 items are selected.
For this data set, is the mean or median a better measure of center? Explain your reasoning.
Problem 4
Clare and Priya each took a random sample of 25 students at their school.
- Clare asked each student in her sample how much time they spend doing homework each night. The sample mean is 1.2 hours, and the MAD is 0.6 hours.
- Priya asked each student in her sample how much time they spend watching TV each night. The sample mean is 2 hours, and the MAD is 1.3 hours.
-
At their school, do you think there is more variability in how much time students spend doing homework or watching TV? Explain your reasoning.
-
Clare estimates the students at her school spend an average of 1.2 hours each night doing homework. Priya estimates the students at her school spend an average of 2 hours each night watching TV. Which of these two estimates is likely to be closer to the actual mean value for all the students at their school? Explain your reasoning.
Problem 5
Adult elephant seals generally weigh about 5,500 pounds. If you weighed 5 elephant seals, would you expect each seal to weigh exactly 5,500 pounds? Explain your reasoning.
Problem 6
Find each difference.
-
the difference of -5 and 6
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the difference of 35 and -8
-
\(\frac25 - \frac35\)
-
\(\text-4\frac38 - (\text-1\frac14)\)