Chapter 2
Descriptive Statistics
4.
A scatter diagram showing the relationship between time spent on the website and the amount spent
follows:
The sample correlation coefficient between these two variables is .580. The scatter diagram and the
sample corre
Chapter 2
Descriptive Statistics
5.
A scatter diagram showing the relationship between the number of pages viewed and the amount
spent follows:
The sample correlation coefficient between these two variables is .724. The scatter diagram and the
sample corr
Graduation Rate Residual Plot
30
Residuals
20
10
0
-10
0
20
40
-20
60
80
100
120
Graduation Rate
The residuals appear to have a relatively constant variance and do not appear to be badly skewed at any value
of displacement. However, the mean residual apea
Student-Faculty Ratio Residual Plot
30
Residuals
20
10
0
-10
-20
0
5
10
15
20
25
Student-Faculty Ratio
The residuals appear to have a relatively constant variance with a mean of zero, and do not appear to be badly
skewed at any value of displacement.
Beca
more at low graduation rates alumni because they feel the university is in greater need of support, and they
give more at high graduation rates because they are recognizing the universitys exceptional performance. If
this explanation is reasonable, it als
Chapter 4
Regression Analysis
Case Problem: Alumni Giving
1.
Descriptive statistics for graduation rate, % of classes under 20, student-faculty ratio, and alumni giving are
shown below.
Graduation
Rate
% of Classes
Under 20
Student-Faculty
Ratio
Alumni
Gi
Descriptive Statistics
Chapter 2
Descriptive Statistics
Solutions:
1.
2.
a.
Quantitative
b.
Categorical
c.
Categorical
d.
Quantitative
e.
Categorical
a.
The top 10 countries according to GDP are listed below.
Country
Continent
United States
North America
Descriptive Statistics
21.
e.
The box plots show that science teachers spend more hours working per week than English teachers.
The box plot for science teachers also shows that most science teachers work about the same amount
of hours; in other words, th
Chapter 2
Descriptive Statistics
3.
Summary by Type of Browser
Frequency
Total Amount
Spent ($)
Average Amount
Spent ($)
Firefox
16
1228.21
76.76
Internet Explorer
27
1656.81
61.36
Other
7
521.39
74.48
Browser
Internet Explorer was used by 27 of the 50 sh
Chapter 2
Descriptive Statistics
6.
Ascatterdiagramshowingtherelationshipbetweenthenumberofpagesviewedandthetimespent
onthewebsitefollows:
The sample correlation coefficient between these two variables is .596. The scatter diagram and the
sample correlati
Unit2:Basics:DataDescription
Leo'sDataMine
DescribingandSummarizingData
Working with Data
Histograms
Outliers
Summary
Creating Histograms in Excel
Central Values for Data
The Mean
The Median
The Mode
Summary
Finding The Mean In Excel
Finding The Median In