LibraryPirate

54 CHAPTER 2 DESCRIPTIVE STATISTICS
treatment of nonathletes with spondylolysis, but no information existed on the results of this type
of surgery in athletes. In a retrospective study, the authors found 20 subjects who had the surgery
between 1993 and 2000. For these subjects, the data below represent the duration in months
of follow-up care after the operation.
2.5.7 See Exercise 2.3.1.
2.5.8 See Exercise 2.3.2.
2.5.9 See Exercise 2.3.3.
2.5.10 See Exercise 2.3.4.
2.5.11 See Exercise 2.3.5.
2.5.12 See Exercise 2.3.6.
2.5.13 See Exercise 2.3.7.
103 68 62 60 60 54 49 44 42 41
38 36 34 30 19 19 19 19 17 16
Source: Satoshi Nozawa, Katsuji Shimizu, Kei Miyamoto,
and Mizuo Tanaka, “Repair of Pars Interarticularis Defect by
Segmental Wire Fixation in Young Athletes with Spondylolysis,”
American Journal of Sports Medicine, 31 (2003),
359–364.
2.5.14 In a pilot study, Huizinga et al. (A-14) wanted to gain more insight into the psychosocial consequences
for children of a parent with cancer. For the study, 14 families participated in semistructured
interviews and completed standardized questionnaires. Below is the age of the sick parent
with cancer (in years) for the 14 families.
37 48 53 46 42 49 44
38 32 32 51 51 48 41
Source: Gea A. Huizinga, Winette T.A. van der Graaf,
Annemike Visser, Jos S. Dijkstra, and Josette E. H. M.
Hoekstra-Weebers, “Psychosocial Consequences for Children
of a Parent with Cancer,” Cancer Nursing, 26 (2003),
195–202.
2.6 SUMMARY
In this chapter various descriptive statistical procedures are explained. These include the
organization of data by means of the ordered array, the frequency distribution, the relative
frequency distribution, the histogram, and the frequency polygon. The concepts of
central tendency and variation are described, along with methods for computing their
more common measures: the mean, median, mode, range, variance, and standard deviation.
The reader is also introduced to the concepts of skewness and kurtosis, and to
exploratory data analysis through a description of stem-and-leaf displays and box-andwhisker
plots.
We emphasize the use of the computer as a tool for calculating descriptive measures
and constructing various distributions from large data sets.