What is important about the normal distribution that makes it different
from other continuous distributions?
How is the standard normal distribution defi ned?
For a normal distribution, what percentage of the distribution is within
one standard deviation of the mean?
What percentage of the normal distribution falls with two standard devia-
tions of the mean?
How are the median, mean, and mode related for the normal
distribution
What two parameters determine a normal distribution?
In a laboratory in a hospital where you are testing for subjects with low -
density lipoprotein and the distribution for healthy individuals is a par-
ticular known normal distribution, how would use this information to
defi ne abnormal amounts of lipoprotein?
What are degrees of freedom for a t - statistic for the sample mean?
How is the t distribution related to the normal distribution? What is dif-
ferent about the t statistic particularly when the sample size is small?
Assume that the weight of women in the United States who are between
the ages of 20 and 35 years has a normal distribution (approximately),
with a mean of 120 lbs and a standard deviation of 18 lbs. Suppose you
could select a simple random sample of 100 of these women. How many
of these women would you expect to have their weight between 84 and
156 lbs? If the number is not an integer, round off to the nearest integer.
Given the sample population of women as in 11, suppose you could
choose a simple random sample of size 250. How many women would
you expect to have weight between 102 and 138 lbs? Again round off to
the nearest integer if necessary.
The following table shows patients with rheumatoid arthritis treated with
sodium aurothiomalate (SA). The patients are divided into those that had
adverse reactions (AE) and those that didn ’ t. In addition to SA, their age
is given. Of the 68 patients, 25 did not have AEs and 43 did (Table 4.1 ).
(a) Construct a stem - and - leaf diagram for the ages for each group.
(b) Construct a stem - and - leaf diagram for the total dose for each group.
(c) Do a side - by - side comparison of a box - and - whisker plot for age for
each group.
