Stat 401B
Lab 1
Due September 6, 2005
1
Use JMP to analyze the data in problem 1 below. It is not sufficient to simply hand
in JMP output. You must answer the questions completely. Hand in the JMP output
attached at the end of your written solutions.
1. An article in the Journal of the American Medical Association examined whether the true
mean body temperature is 98.6 degrees Fahrenheit. Data that are available on the course Web
site were constructed to match as closely as possible the histograms and summary statistics
presented in that article. Go to the course Web site
www.public.iastate.edu/∼wrstephe/stat401.html
to get the JMP or TXT file of the data. Follow the instructions to get the data into JMP.
(a) Summarize the temperature data graphically by creating a histogram, box plot and normal probability plot. Referring to these graphs, describe the distribution of temperature.
Refer to each graph separately and comment on the shape of the distribution, if there
are any possible outliers and describe what in the graph supports your statements.
(b) Summarize the data numerically and report a five number summary, the sample mean
and sample standard deviation.
(c) What does the comparison of the mean to the median tell you about the distribution of
values?
(d) Report the 95% confidence interval for the population mean temperature. Give an
interpretation of this interval and the confidence level.
(e) Test the hypothesis that the population mean temperature is 98.6 against an alternative
that the population mean viscosity is not 98.6.
The column Sex is coded so that 1=male and 2=female. Make sure the Sex column
has a Data type that is Character and a Modeling type that is Nominal.
(f) Summarize the temperature values graphically and numerically for each sex. How do
males compare to females?
(g) Do the males differ significantly from the females in terms of average body temperature?
Perform the appropriate test of hypothesis. Use α=0.05.
(h) Report the value of a 98% confidence interval for the difference between the mean body
temperatures for males and females. Give an interpretation of this interval use the
interval to test to see if the difference in mean temperatures between males and females
is statistically significant.
(i) It appears that the test of hypothesis and the confidence interval reach different conclusions about whether males differ significantly from females in terms of mean temperature.
Explain what is happening.
2. On a separate piece of paper write a brief summary of what you have learned about body
temperature from the analysis of these data.