3.3 The following set of data is from a sample of n= 7
12 7 4 9 0 7 3
a. Compute the mean, median, and mode.
b. Compute the range, variance, standard deviation, and coefficient of variation.
c. Compute the Z scores. Are there any outliers?
d. Describe the shape of the data set.
3.8 The file FastFoodcontains the amount that a
sample of nine customers spent for lunch ($) at a
fast-food restaurant:
Amount
7.38
8.46
5.03
6.45
8.47
4.20
5.86
7.54
9.87
a. Compute the mean and median.
b. Compute the variance, standard deviation, range, and coefficient of variation.
c. Are the data skewed? If so, how?
d. Based on the results of (a) through (c), what conclusions can you reach concerning the amount that customers spent for lunch?
3.13 Is there a difference in the variation of the yields of different types of investments? The file CDRate contains the yields for a one-year certificate of deposit (CD) and a five-year certificate of deposit (CD), for 23 banks in the United States, as of April 4, 2011.
Bank One-Year Five-Year
AIG 1.15 2.20
Ally 1.24 2.40
American 0.85 2.35
Astoria Federal 0.75 2.65
Bank of Internet USA 1.21 2.49
Centennial 0.60 2.12
Colorado federal 1.25 2.30
Discover 1.20 2.30
First Internet Bank of Indiana 1.00 2.40
Goldwater 1.24 2.39
Intervest National 1.20 2.39
Lone Star 0.80 2.38
MetLife 1.25 1.90
Nationwide 1.20 2.55
newDominion 1.16 2.00
Nova 0.90 2.25
OneWest 1.20 2.55
Salem Five 0.60 2.00
State farm 0.80 2.43
National Republic Bank of Chicago 1.26 2.27
Transportation Alliance 1.20 2.28
USAA 0.91 2.25
VirtualBank 1.11 2.22
a. For one-year and five-year CDs, separately compute the
variance, standard deviation, range, and coefficient of
variation.
b. Based on the results of (a), do one-year or five-year CDs
have more variation in the yields offered? Explain.
3.21 The file ChocolateChip contains the cost (in cents)
per 1-ounce serving, for a sample of 13 chocolate chip
cookies. The data are as follows:
54 22 25 23 36 43 7 43 25 47 24 45 44
a. Compute the first quartile (Q1) the third quartile (Q3)
and the interquartile range.
b. List the five-number summary.
c. Construct a boxplot and describe its shape.
3.43 College football players trying out for the NFL are
given the Wonderlic standardized intelligence test. The file
Wonderlic contains the average Wonderlic score of football
players trying out for the NFL and the graduation rate for
football players at selected schools.
School Wonderlic Graduation%
Stanford 28.8 85
Purdue 25.3 63
California 25.2 48
UCLA 24.0 55
Oregon 23.5 68
Wisconsin 23.2 56
Iowa 23.0 58
Oregon State 22.8 44
Nebraska 22.6 63
Notre Dame 22.5 77
Boston College 22.0 78
Colorado 21.8 43
Michigan 21.7 57
Virginia 21.5 75
Texas A & M 21.0 50
Florida 20.8 42
Ohio State 20.8 52
Penn State 20.7 74
Virginia Tech 20.7 58
Southern California 20.3 58
West Virginia 20.3 46
Arizona State 20.2 44
Kansas State 19.8 61
Georgia 19.8 53
Texas 19.7 34
North Carolina State 19.6 42
Florida State 19.4 49
Oklahoma 19.0 40
North Carolina 18.9 53
Arkansas 18.6 35
Auburn 18.5 48
LSU 18.5 42
Clemson 18.3 51
Alabama 18.2 49
South Carolina 17.9 54
Tennessee 17.7 38
Michigan State 16.6 41
Miami (Florida) 16.3 57
a. Compute the covariance.
b. Compute the coefficient of correlation.
c. Based on (a) and (b), what conclusions can you reach about the relationship between the average Wonderlic score and graduation rate?