Basic Statistics

PROBLEMS 47

PROBLEMS

4.1

4.2

4.3

4.4

4.5

4.6

4.7

4.8

4.9

Make a stem and leaf graph of the first five rows of the blood cholesterol data

in Table 2.1 (50 observations). Do you see an excess of 0’s or 5’s?

Use the stem and leaf graph from Problem 4.1 to assist you in ordering the data.

From the ordered data, make a relative frequency table such as that given in

Table 4.5.

Make a histogram of the percentages from Problem 4.2. Does the distribution

appear to be symmetric? Approximately what percentage of the cholesterol

levels lie below 240 mg/100 mL? What percent lie above 250 mg/100 mL? Does

a cholesterol level of 280 appear to be extremely high for this sample?

Draw a frequency polygon from Problem 4.3.

Using the results from Problem 4.2, draw the cumulative frequency in percent.

What percent of the observations are below 240 mg/mL using this display?

Using an available statistical package, try to repeat what you obtained in Prob-

lems 4.1-4.5. Compare the results and describe any problems you may have

had.

Measure the length of the index finger in centimeters for each person in the

class. Using this data, repeat Problems 4.1 and 4.2 either by hand or using a

statistical program, and answer the first question in Problem 4.3.

Make a histogram from a sample of 50 single numbers from Table A.l in

Appendix A. Sketch what you would expect the histogram to look like if a very

large sample was drawn. Use a statistical program to obtain the histogram.

Describe a set of data that you would expect to see skewed to the right.

REFERENCES

Chambers, J. M., Cleveland, W. S., Kleiner, B. and Tukey, P. A. [1983]. Graphical Methods

Cleveland, W. S. [1985]. The Elementsof Graphing Data, Monterey, CA: Wadsworth, 123-153.

Cleveland, W. S. [ 19931. Visualizing Data, Summit, NJ: Hobart Press, 16-86.

Evans, M. J. [2005]. Minitab Manual for Introduction to the Practice of Statistics, 5th ed., New

Hill, B. A. [1961]. Principles ofMedical Statistics, New York: Oxford University Press, 52.

Koschat, M. A. [2005]. A case for simple tables, The American Statistician, Vol. 59, No. 1,

Tufte, E. R. [ 19901. Envisioning Information, Cheshire, CT Graphics Press.

for Data Analysis, Belmont. CA: Wadsworth, 7-69.

York: W.H. Freeman, 41.

31-40.