Download Review: Inferences Name Math 7/8 Period: ______ Due Date: 1

Review: Inferences
Name _______________________________________
Math 7/8
Period: _________
Due Date: _______________
1. What is the difference between a measure of center and a measure of variability?
2) How can you determine if a sample is valid verses invalid?
3) Give an example of a simple random sample.
The table below shows minutes of studying of 20 female 7th grade students and 20 male 7th
grade students for a math test.
Males
Females
84
98
112
120
82
106
116
126
88
98
114
120
94
106
122
126
90
102
116
124
98
110
124
128
94
104
118
124
100
110
124
136
94
108
118
132
104
112
124
162
4) Find the mean study time:
males:
females:
5) From this sample it appears that boys study more. Based on this sample, is this a valid
conclusion? Explain why or why not.
6) Ms. Mourdock took a survey of the students in her classes to see how many students are
going to attend the school dance. She surveyed 28 students, and 14 said they would attend. If the
school has 320 students, how many students might Ms. Mourdock expect to attend the dance?
7) In a poll of Mrs. Richard’s math class, 75% of the students say that math is their favorite
academic subject. The yearbook staff wants to have a special page dedicated the student’s
favorite subject. Is this a valid conclusion? Why or why not?
8) The yearbook staff wants to have a special page dedicated to the favorite subject of students
at McCleskey. How could the yearbook staff could gather data to determine which subject is the
most popular?
9) James conducted a survey to determine which flavor is the most popular at Baskin Robbins.
He asked all of the students in the cafeteria during lunch. What might you say about James’ poll
sample and his survey?
10) Jamie is taking a survey to find out the most popular type of food in Marietta. Why would
surveying customers leaving Olive Garden not be a representative sample?
11) The student council was trying to decide if they should sell blue shirts or green shirts to the
students at Blackhawk Middle School. Student Council members asked the 30 students in Mrs.
Smith’s 7th grade social studies class.
Blue: 65%
Green: 35%
If there are 550 students who attend Blackhawk, is the sample valid to predict which shirt color
the Student Council should order to sell? Why or why not?
12) The tables below show the number of DVDs sold at two different stores over a two-week
period. Find the median for each set of data. How do the medians for the number of DVDs sold in
the two stores compare?
Store A
Store B
20
26
27
20
21
23
28
28
29
25
26
26
29
32
32
31
33
33
33
35
37
34
38
39
38
39
39
42
Seven students were asked how many books they read over the summer. The results are
as follows:14, 15, 18, 18, 20, 21, 25
13) What is the mean of the data?
14) What is the mean absolute deviation (MAD) of the data?
15) The double box plot shows the heights in inches for the players on two professional basketball teams. Compare
their centers, variations, and spread. Which set of data has the most variability? Write an inference you can draw
about the two populations.
16) The double dot plot shows the number of minutes two students spent practicing the piano. Compare their centers
and variations, round to the nearest tenth.) Which is the better measure of center for this data? Explain. Write an
inference you can draw about the two populations.
17) Given the following data sets, find the set with the most variability.
mean
Q1
median
Q3
set 1
50
20
40
60
How did you figure this out?
set 2
50
30
45
65
set 3
60
50
65
95
set 4
45
30
45
60