Unit 4 - Inferences Created by Educational Technology Network. www.edtechnetwork.com 2009

POWERPOINT JEOPARDY Biased vs. Unbiased Sampling Methods Making Predictions MMMR Inferencing 10 10 10 10 10 20 20 20 20 20 30 30 30 30 30 40 40 40 40 40 50 50 50 50 50

The first 50 people exiting a movie are surveyed to find out what type of movie people in the town like to see.

Biased

A librarian randomly chooses 100 books from the library’s database to calculate the average length of a library book.

unbiased

A city-hall employee surveys 100 customers at a restaurant to learn about the jobs and salaries of city residents.

biased

Smith surveys 35 people in the purchase department of his company to determine the favorite hobbies of the employees of the company.

biased

Jacy surveys 100 people who were randomly chosen from the membership list of a club to determine the most popular TV show among the members of the club.

unbiased

Football Game: Student Attendance Arnie surveys 80 students by randomly choosing names from the school directory. Vic surveys 28 students that were sitting near him during lunch.

Group #1

Lone Star Cars: Customer Satisfaction Nadia surveys 200 customers on the car lot one Saturday morning. Daria mails surveys to 100 randomly-selected customers.

Group #2

Midville Morning News: Subscription Renewals Suzanne surveys 80 subscribers in her neighborhood. Vonetta telephones 150 randomly-selected subscribers.

Group #2

Favorite Games of Residents Jim surveys 100 people exiting a football stadium. Jane randomly surveys 200 people from the phone directory.

Group #2

Computer Literacy Among Teachers Lisa surveys all high school math teachers. Gail surveys every eighth teacher on an alphabetical list.

Group #2

11 out of 50 students said they would enter the medical field 11 out of 50 students said they would enter the medical field. Predict how many students out of 500 would enter the medical field.

110

Three out of every 10 students ages 6 – 14 have a magazine subscription. Suppose there are 30 students in Annabelle’s class. About how many will have a magazine subscription?

9

Members of the drama club plan to sell popcorn as a fundraiser for their Shakespeare production. If the club orders 400 boxes of popcorn to sell, how many boxes of caramel popcorn should they order? Flavor Number butter 33 cheese 15 caramel 27

144

A factory produces 12,000 computers per week A factory produces 12,000 computers per week. The manager of a factory claims that fewer than 50 defective computers are produced each week. In a random sample of 500 computers, 2 were defective. Is the manager’s claim likely to be true?

True, 48

Five out of seven teens said they do homework every night Five out of seven teens said they do homework every night. What is a reasonable prediction for the number of teens out of 980 who would NOT do homework every night?

280

What is the mean, median, mode, and range of the data below? 6, 14, 16, 16, 16, 17, 18, 18, 20

Mean: 15.7 Median: 16 Mode: 16 Range:14

What is the MAD of the data below? 12, 13, 15, 17, 22

MAD: 2.96

The following data represents the number of glasses of water Leann consumed in one day: 1, 3, 4, 4, 4, 5, 7, 12. Which measure of center best describes the number of glasses of water Leann consumed?

median

Women’s Heights 61, 65, 68, 58, 60, 65, 70, 63, 65, 62 Find the mean, median, range, and interquartile range of the data above.

Mean: 63.7 Median: 64 Range:12 IQR: 4

For 7th and 8th grade students, the total number of hours spent playing extracurricular sports was collected for four days and is shown below. Compare the mean absolute deviations (MAD) of the hours for each grade.   7th grade: 125, 135, 140, 138 8th grade: 205, 195, 228, 100

Mean: 134.5 MAD: 4.75 Mean :182 MAD: 41

Quiz Scores Green Acres: 6, 11, 12, 13, 14, 14, 14, 14, 15, 16, 20 Which measure of center should Green Acres use to brag about their scores?

Mean: 13.5 Median: 14

Which movie has the greater median? By how much?

B, 2

Which movie is the most predictable?

A, smaller IQR

Which group watches the most TV?

Group 1 Median:35 Group 2

Find the following: Group 1 Group 2 Mean: Mean: Median: Median: Range: Range:

Group 1 Group 2 Mean: 35 Mean:26 Median: 35 Median:27 Range: 6 Range:10 IQR: 4 IQR: 4