MATH 131
Lab 2
8/11
The goal of this lab is to organize your data from Lab 1 into frequency distributions and graphs.
(3 points)
Part 1: V1, Qualitative Data
A.
B.
C.
D.
Prepare a frequency and relative frequency distribution for your qualitative data V1 in the
format noted below. Fill in the appropriate data values and frequencies for your data from
Lab 1.
Prepare a PIE CHART for your data.
Prepare a PARETO CHART (See p. 59) for your data.
Write a one-sentence explanation about what these charts tell you about your data and
whether you expected this result. Which graph did a better job of conveying that
information?
(3 points)
A.
B.
C.
B.
C.
D.
V2, Quantitative Data
List the name for V2, the quantitative variable for this part of the lab. Organize your data
into a frequency distribution using either at least 5 classes or single values, as appropriate
for your data. See examples on the next page
Prepare a relative frequency histogram to accompany your table. Label clearly and
completely. (See p. 44)
Comment about your histogram. Use words like "symmetric", "skewed left or right", as
appropriate. (See p. 73)
(4 points)
A.
Part 2:
Part 3:
V3, Quantitative Data
List the name for V3 , the quantitative variable for this part of the lab. Prepare a frequency
distribution for your data, using at least 5 classes. See the example on next page.
Prepare a frequency histogram. Label it clearly. (See p. 44)
Prepare a frequency polygon using class midpoints. (See p. 45) Label carefully.
What does each of the two graphs communicate to you about your data? Which would you
prefer to use? EXPLAIN.
Part 1 EXAMPLE:
Values for Qualitative Data
Democratic
Republican
Frequency (f)
22
18
To create the Pie Chart in
Minitab,
Click Graph
Pie Chart
Chart Raw Data
relative frequency (rf)
22/40 = 55%
18/40 = 45%
Click in the Categorical
Variables window. Highlight
the column with V1.
Select
Click Labels
Add an appropriate title.
1
Select Slice Labels
check off Category name
Percent
OK
OK
MATH 131
Lab 2
8/11
Part 2 EXAMPLES:
Choice 1: Single Values
If your data does not have much spread (i.e. a few data values are repeated many times), list each
data value in a separate class in your table.
** For the data from the U.S. Senators: "How many terms have they served?" the table would look
like:
Number of terms
1
2
3
4
5
Number of Senators,
frequency, f
12
16
7
4
1
Relative frequency
12/40 = 0.30
16/40 = 0.40
7/40 = 0.175
4/40 = 0.10
1/40 = 0.025
Choice 2: Groups
If your data is spread out, with no or few repeating data values, form a frequency distribution. Be
sure to make at least 5 classes. Follow all rules discussed in class about forming groups. (See p.
40-42)
** If your data was the number of movies people rent in a year, and the values range from 0 to 52,
you would group your data. It might look as follows:
# of Movies
0 -- 9
10 – 19
20 – 29
30 – 39
40 – 49
50 – 59
Frequency, f
7
11
14
6
0
2
Relative frequency
7/40 = 0.175
11/40 = 0.275
14/40 = 0.35
6/40 = 0.15
0
2/40 = 0.05
Part 3 EXAMPLE:
Age
35 – 44
45 – 54
55 – 64
65 – 74
75 – 84
Frequency, f
5
6
17
8
4
Class Midpoint
39.5
49.5
59.5
69.5
79.5
2
Class boundaries
34.5 – 44.5
44.5 – 54.5
54.5 – 64.5
64.5 – 74.5
74.5 – 84.5
Class boundaries
–0.5 – 9.5
9.5 – 19.5
19.5 – 29.5
29.5 – 39.5
39.5 – 49.5
49.5 – 59.5