a, 2.16
2.17
, ,
, ,
, ,
Class Midpoint Weight Frequency
White Households Nonwhite Households
Income Frequency
Relative Frequency
Relative 1000’s
1000’s Frequency
1000’s Frequency
The American Statistician,
Statistical Abstract of the United States 1990,
56
OURCE
OURCE
2.99 1
3.01 4
3.03 4
3.05 4
3.07 7
3.09 17
3.11 24
3.13 17
3.15 13
3.17 6
3.19 2
3.21 1
[ 0 5 3926
.0639 2235
.1561 [ 5 10
7930 .1290
2679 .1871
[ 10 15 7852
.1277 2119
.1480 [ 15 25
14683 .2388
3351 .2341
[ 25 35 12956
.2107 2066
.1443 [ 35 50
14133 .2299
1867 .1304
CHAPTER 2 DESCRIBING PATTERNS IN DATA
S : Adapted from Table 1 in Vardeman, S.,
“What About Other Intervals?” Vol. 46, No. 3, Aug. 1992, p. 195.
S :
U.S. Dept. of Commerce, Bureau of the Census, Washington, D.C., pp. 444 – 445.
a. Complete the table by adding a relative frequency column and a density
column. b.
Using the results in part plot the density histogram for sizes of raise.
Comment on the general appearance of the density histogram. The following table gives the class midpoint weights in grams and class
frequencies for 100 newly minted U.S. pennies.
a. Create a frequency distribution for these data by specifying the class limits
assume all intervals are of the same length and adding a relative frequency column.
b. Plot the relative frequency histogram of penny weights, and comment on its
appearance. Would the configuration of the histogram change if densities rather than relative frequencies were used in its construction? Discuss.
The accompanying table gives the frequency distributions of household incomes for white and nonwhite families in the United States as of 1987. We report only
household incomes up to 50,000.
a. Plot the relative frequency histograms for white household incomes and
nonwhite household incomes. Compare the two histograms. Can you make any statements about the distribution of white household incomes relative
to the nonwhite household incomes? Discuss.
b. Add a column of densities to each of the income distributions. Plot the
density histograms for white household incomes and nonwhite household
v v
v
2.5 NUMERICAL SUMMARIES OF DATA DISTRIBUTIONS
Kategori