1. Unit 8 Statistics Quiz Review
Ch. 10
Lessons 1, 2, 4 & 5

2. 10-1
Make Predictions
Statistics: Collecting, organizing, and interpreting data
Survey: A method of collecting information
Population: The group being studied
Sample: Part of the group that is surveyed
Must be representative of the population!

3. Make Predictions Using Ratios:
Find the probability/results for the original problem/survey and write as a simplified fraction
Set up a proportion
New number/population goes on bottom of 2nd fraction
Solve by using cross-products
Label answer!

4. A survey found that 17 out of 20 teens eat breakfast every morning
A survey found that 17 out of 20 teens eat breakfast every morning. What is a reasonable prediction for the number of teens out of 1,280 in a school who eat breakfast every morning?

5. A survey showed that 70% of students would select roller coasters as their favorite ride at an amusement park. Out of 5,000 students, predict how many would NOT select roller coasters as their favorite ride.

6. The table shows the results of a survey at Scobey Middle School about students’ favorite cookies.
There are 424 students
at Scobey Middle School.
About how many can be
expected to prefer chocolate
chip cookies?

7. 10-2 Unbiased and Biased Samples Unbiased = GOOD! (Valid results)
Accurately represents the entire population
Simple Random Sample
Systematic Random Sample
Biased = BAD! (Not valid results)
One or more parts of the population are favored over others
Convenience Sample
Voluntary Response Sample

8. Antwan wants to know how often the residents in his neighborhood go to the beach. Which sampling method will give valid results?
A. He asks all the members of the swim team at his school
B. He asks all his family members and friends
C. He posts a question on a community Web site
D. He asks three random households from each street in his neighborhood

9. Determine whether the conclusion is valid. Justify your answer.
To determine the most common injury cared for in an emergency room, a reporter goes to the same hospital every afternoon for one month during the summer and observes people entering the emergency room. She concludes that second degree sunburn is the most common injury.

10. To evaluate the defect rate of its memory chips, an integrated circuit manufacturer tests every 100th chip off the production line. Out of 100 chips tested, one chip is found to be defective. The manufacturer concludes that 3 chips out of 300 will be defective.

11. MMMR Mean: average of a data set Median: middle of a data set
Add the numbers and divide by how many there are
Median: middle of a data set
Put the numbers in order and cross out number on both ends until you find the number in the middle
If even amount of numbers, find the average of the middle two
Mode: number(s) that occur the most often
Range: spread of the data
Subtract the lowest number from the highest

12. The number of toys donated by students in 12 classes is shown below
The number of toys donated by students in 12 classes is shown below. Find the mean, median, mode, and range of the data.
24, 33, 59, 19, 16, 29, 20, 17, 31, 23, 16, 25

13. 10-5 Select an Appropriate Display
Bar Graph: show the number of items in specific categories
Box Plot: show measures of variation (median) for a set of data
Circle Graph: compare parts of the data to the whole (percents)
Double Bar Graph: compare two sets of categorical data
Histogram: show frequency of data divided into equal intervals
Line Graph: show change over a period of time
Line Plot: show frequency of data with a number line

14. Select an appropriate display for each situation
Select an appropriate display for each situation. Justify your reasoning.
ages of all students at a summer camp
test grades for a class, arranged in intervals

15. 10-4 Compare Populations Median: breaks data in half
First Quartile: median of first half of data
Third Quartile: median of second half of data
Interquartile Range: Third quartile – first quartile

16. You can draw inferences about two populations in a double box plot or double dot plot by comparing their centers and variations
If neither set of data is symmetric or one set of data is symmetric:
Use median for measure of center AND
Use interquartile range for measure of variation (spread of the data)

17. The double line plot shows the number of students who attended the home games of the baseball team for two recent seasons.

18. Which of the following statements is not true?
A. The attendance for 2009 was more varied.
B. The attendance for 2010 was more consistent.
C. The attendance for 2009 peaked at 23 students.
D. The attendance for 2010 ranged from 20 to 27.

19. Compare the centers and variations of the two populations
Compare the centers and variations of the two populations. Round to the nearest tenth if necessary. Write an inference you can draw about the two populations
The double plot shows the daily attendance for two fitness clubs for one month