Unit 2 Inferences

Dr. Riggins, the school principal is gathering data about students and homework completion.  To get valid results, which survey method should she use?

• Post a link to his survey questions on the school website.
• Survey the first 30 students who walk into the building on Monday morning.
• Ask each homeroom teacher to select 4 students to answer his survey.
• Have the computer randomly generate a list of students to answer his survey.

Briana wants to conduct a survey to determine what type of salad dressing is preferred by most students at Gwinnett Middle School. Which of the following methods is the best way for her to choose a random sample of the students at her school?     

• Select students in her math class. 
• Select members of the chess club. 
• Select ten students from each homeroom.
• Select members of the girls’ basketball team. 

Identify the population and sample in the following survey: To gauge student preference of a new school mascot, the Student Council President surveyed the members of the school soccer team.

• Population: students in the school  Sample: school soccer team
• Population: school soccer team Sample: students in the school
• Population: school soccer team Sample: Student Council President
• Population: students in the school  Sample: school mascot

Analyze the items below and determine the sample that is biased.                                                             

• Asking every fifth student in the sixth grade his or her opinion about something.
• Each student’s name is written on a slip of paper and placed in a box.  One slip is selected for a prize.
• A teacher randomly chooses names from a list of all the students in a school.
• Use the weather patterns in KY to predict the weather for the entire United States.

Sam conducted a survey to determine the favorite flavor of ice cream in his hometown.  Fifteen of the fifty people he surveyed liked strawberry best.  How many of the 3,500 residents in the town would you expect to like strawberry best?

• 150
• 560
• 750
• 1050 

The Student Council at a new junior high school surveyed 5 students from each of the 10 homerooms to determine what mascot students would prefer. The results of the survey are shown below. If there are 375 students at the school, predict how many students prefer a tiger as the school mascot.    

• 28
• 96
• 138
• 210

Manny surveyed 24 of his classmates about their vacation plans.  The bar graph shows the results.   Manny’s class is representative of the entire school.  What is a reasonable estimate for how many of the 300 students in the school have no vacation plans?

• 50 students 
• 75 students 
• 100 students 
• 150 students 

A box holds 10 red buttons, 30 green buttons, 40 blue buttons, and 20 yellow buttons.  A sample of 10 buttons is randomly removed, tallied, and returned to the box.  Three other samples are taken in the same way.  The table shows the results.  Which sample is the best representation of the buttons in the box?

• Sample #1
• Sample #2
• Sample #3
• Sample #4

What can be said about the data points when the variability (distribution) is great?                                                     

• the data is close together
• the data is far apart
• the data is reliable
• it cannot be determined

Use the box-and-whisker plots to determine which statement is not true.

• The median of the men’s ages is greater than the median of the women’s ages.
• The interquartile range of the men’s ages is greater than the interquartile range of the women’s ages.
• The youngest member of the club is a woman.
• The range of the men’s ages is greater than the range of the women’s ages.