MATH 3070: Worksheet No.1
NAME:
1. Report your findings regarding Exercise 3.10/3.11. (Data file ex3-10.csv)
(a) Give a short description of the data and the variable(s).
(b) Construct a relative frequency histogram for the data, and describe the shape of the relative
frequency histogram.
(c) If you were transferred by your employer to one of the 24 cities, what is the probability that
your city taxes would be more than $900?
(d) Construct a stem and leaf plot for the data. Is the relative frequency histogram or the stem
and leaf plot more informative?
2. Report your findings regarding Exercise 3.13/3.14. (Data file ex3-13.csv, ex3-14.csv)
(a) Give a short description of the data and the variable(s).
(b) Construct separate relative frequency histograms for the survival times of both the therapies.
Does the new therapy appear to generate a longer survival time?
(c) Construct a relative frequency histogram for this combined data set. Does the plot indicate
that the data are from two separate populations?
3. Report your findings regarding Exercise 3.32. (Data file ex3-32.csv, ex3-32b.csv)
(a) Give a short description of the data and the variable(s). Are the two data sets essentially the
same data? What are the differences?
(b) Compute the mean and median for the ratio, ignoring the type of feeder. Indicate which of
the data files you used. Comment on the relative sensitivity of the mean and median to
extreme values in a data set.
(c) Compute the mean and median separately for each type of feeder. Indicate which of the data
files you have used. Comment on the relative sensitivity of the mean and median to extreme
values in a data set.
(d) Which measure, mean or median, would you recommend as more appropriate measure of
the DDE to PCB level for both types of feeders?
4. Report your findings regarding Exercise 3.33. (Data file ex3-33.csv)
(a) Give a short description of the data and the variable(s).
(b) Calculate the measures of center (if possible) for the 11 patients.
(c) If the survival times of the two patients who left the study were obtained, how would these
new values change the values of the summary statistics calculated in (b)?
5. Report your findings regarding Exercise 3.34. (Data file ex3-34.csv)
(a) Give a short description of the data and the variable(s).
(b) Calculate the measures of center for the 14 engines.
(c) What are the implications of computing the measures of center when some of the exact
failure times are not known?
6. Report your findings regarding Exercise 3.37/38. (Data file ex3-37.csv)
(a) Give a short description of the data and the variable(s).
(b) Compute the mean and median separately for the three groups.
(c) Average the three group means and the three group medians. Then compute the mean and
median for the complete set of 30 measurements. Discuss your findings from these
