Introduction
to Minitab 14: Exercises
Note: the version in the Math Lab is Minitab 16,
while 14 is the version that came with your books.
For an overview of the Minitab program, read the
introduction in your textbook on pages xv to xviii. There are also some instructions on creating
histograms and bar graphs on pp. 59 – 60.
1)
A sample of those who work in Manhattan but live elsewhere was taken
and the subjects were asked how they travel to work each day. The responses are compiled below:
Bus 57
Train 85
Drive (alone) 49
Drive (carpool) 15
Ferry 38
Company Van 22
Other
9
a.
Construct a bar graph displaying this data. To do this, enter the categories in one
column and the frequencies in another.
Select Graph>Bar Chart and select the option “bars represent
values from a table.” Enter the column
with the category name in “categorical variable” and the count column in the
“graph variables”.
b.
A Pareto graph is a bar chart in which the variables are ordered by
frequency. To construct one, open the Bar
Chart dialog box again and click on Bar Chart Options. Then choose to order your bars by decreasing
Y. Why might a reader of this survey be
interested in a Pareto graph?
c.
Would a pie chart be an appropriate display for this data set? Explain.
If the answer is yes, construct one by selecting Graph>Pie
Chart.
2)
Enter each of following data sets in a separate column and answer the
following for each one.
a. Use Minitab to construct a
histogram, using 6 or 7 classes. Select Graph>Histogram
to get to the appropriate dialog box. To
control the number of classes, right-click on the graph and select “Edit Bars”.
b. Describe the shape of the
histogram (is it skewed left or right, symmetric, bimodal, etc.)
c. Compute the median and the
mean. To do this, select Stat
>Basic Statistics > Display Descriptive Statistics; this gives you
the mean, median and several other measures all at once. Alternately, you could choose Calc
> Column Statistics to compute the measures one at a time. What is the relationship between the median
and the mean? In other words, which is
larger, or are they approximately equal?
How does this relate to the shape of the histogram? What might cause this relationship?
Set 1: 6, 10, 10, 11, 15, 15, 18, 18, 21, 22, 22, 22, 25, 29, 31, 32, 34,
35, 36, 48, 61
Set 2: 5, 15, 16, 21, 23, 24, 31, 32, 32, 33, 34, 34, 36,
38, 39, 40, 41, 41, 42, 48
Set 3: 5, 13, 17, 18, 18, 19, 26, 26, 28, 30, 31, 33, 33,
38, 39, 39, 42, 48, 50, 61
3) The following are the scores on the Survey of Study Habits and
Attitudes (SSHA) for 18 first-year college women:
154 109 137 115 152 140 154 178 101
103 126 126 137 165 165 129 200 148
Here are the SSHA scores for 20 first-year college men:
108 140 114 91 180 115 126 92 169 146
109 132 75 88 113 151 70 115 187 104
a. We would like to use
side-by-side box-and-whisker plots to compare the women’s and the men’s
scores. To begin, enter the women’s
scores in C1 and the men’s in C2.
b. Use the Graph > Boxplot command to construct a
box-and-whisker plot for each of these data sets. Choose “Simple with multiple Y’s.” Enter
column numbers containing the data sets in the Y (measurement) box.
c. Which group, women or men,
had the higher median score on the SSHA?
d. Which one seems to be more
variable, based on this data? Why?
e. Does either set have any
outliers by the 1.5 IQR criterion?
3)
Open the Minitab worksheet “cities.mtw.” by selecting
File>Open Worksheet and selecting the Data folder. This worksheet contains data for monthly
average temperature for five different cities for one year. Compute the descriptive statistics by selecting
Stat >Basic Statistics > Display Descriptive Statistics.
a.
Which city had the highest mean temperature for the year? The lowest?
b.
Which city had the highest median temperature for the year? The lowest?
How do your answers compare to part a?
c.
Which city had the most variation in temperature over the year? What measure did you use to answer this
question? Would using a different
measure of variation yield a different answer? (specify
which measure and if different, which city.)
5)
A student wonders if tall women tend to date taller men than do short
women. The following is a data set of
the heights (in inches) of six dating couples.
|
Women
(x) |
66 |
64 |
66 |
65 |
70 |
65 |
|
Men
(y) |
72 |
68 |
70 |
68 |
71 |
65 |
a.
Enter the women’s heights in one column and the men’s in another.
b.
Use the Graph>Scatterplot menu
to generate a scatterplot for the age of the man vs. the age of the woman. Select “Simple.” Describe the relationship between the two
variables.
c.
Use the Stat > Basic
Statistics menu to compute the correlation coefficient for this pairs. What does this value tell you?
d.
Use the Stat>Regression>Fitted
Line Plot menu command to calculate the equation of the least-squares
regression line for this data.