52 Chapter 2:Descriptive Statistics
Dogs
Rank Breed 2000
1 Retrievers (Labrador) 172,841
2 Retrievers (Golden) 66,300
3 German Shepherd Dogs 57,660
4 Dachshunds 54,773
5 Beagles 52,026
6 Poodles 45,868
7 Yorkshire Terriers 43,574
8 Chihuahuas 43,096
9 Boxers 38,803
10 Shih Tzu 37,599
11 Rottweilers 37,355
12 Pomeranians 33,568
13 Miniature Schnauzers 30,472
14 Spaniels (Cocker) 29,393
15 Pugs 24,373
16 Shetland Sheepdogs 23,866
17 Miniature Pinschers 22,020
18 Boston Terriers 19,922
19 Siberian Huskies 17,551
20 Maltese 17,446
Source: American Kennel Club, New York, NY: Dogs registered during
calendar year shown.
25.A chemical engineer desiring to study the evaporation rate of water from brine
evaporation beds obtained data on the number of inches of evaporation in each
of 55 July days spread over 4 years. The data are given in the following stem and
leaf plot, which shows that the smallest data value was .02 inches, and the largest
.56 inches..0 2, 6
.1 1, 4
.2 1, 1, 1, 3, 3, 4, 5, 5, 5, 6, 9
.3 0, 0, 2, 2, 2, 3, 3, 3, 3, 4, 4, 5, 5, 5, 6, 6, 7, 8, 9
.4 0, 1, 2, 2, 2, 3, 4, 4, 4, 5, 5, 5, 7, 8, 8, 8, 9, 9
.5 2, 5, 6Find the
(a) sample mean;
(b) sample median;
(c) sample standard deviation of these data.
(d) Do the data appear to be approximately normal?
(e)What percentage of data values are within 1 standard deviation of the mean?