Covering a wart with a piece of duct tape may be as effective in
getting
rid of it as liquid nitrogen freezing, according to an article in the
October
2002 issue of the Archives of Pediatrics & Adolescent Medicine.
Researchers
from Madigan Army Medical Center in Tacoma, Washington, studied 51
patients
ages 3 to 22 with common warts. Twenty-six patients were treated with
duct
tape and 25 were treated with liquid nitrogen, or cryotherapy.
Patients in the tape group, or their parents, were told to leave the
tape
in place for six days, and to replace it if it fell off. After six
days,
they were told to remove the tape, soak the area in water, and file the
wart
with an emery board or pumice stone. After 12 hours without the duct
tape,
they were told to put a new piece on the wart, and continue the cycle
for
two months or until the wart was gone. Patients in the
cryotherapy
group received a standard application of liquid nitrogen on the wart
for
10 seconds. Patients, or their parents, were told to return to the
clinic
every two to three weeks to repeat the freeze for a maximum of six
treatments
or until the wart was gone.
The researchers found that the duct tape treatment completely removed
warts
in 22 of 26 patients, while the liquid nitrogen treatment removed warts
in
15 of 25 patients. From these two sample proportions can we
conclude
that treating a wart with duct tape is better than cryotherapy?
What proportion of the patients using the duct tape treatment
had their
warts completely removed? What proportion of the patients using
the
cryotherapy treatment had their warts completely removed?
Run a test of significance to determine if a greater
proportion
of patients using the duct tape treatment would have successful results
as
opposed to those using the cryotherapy treatment. Report the hypotheses,
P-value, and conclusion. (Stat >
Basic
Statistics > 2 Proportions then click on Summarized
data:
and put the results for the duct tape therapy in for the First
sample:
and the cryotherapy in for the Second sample:. Under Options...,
click on greater than for your alternative hypothesis. Also under
Options... click on
Use pooled estimate of p for test.)
There is a sample size problem in running this
test. Specifically, what is it?
A study of the comparison of the proportion of boys born to
smoking
parents to that of nonsmoking parents was reported on April 20,
2002
by The Lancet, a British medical journal. The results of
the
article showed that couples who smoke around the time of conception are
less
likely to produce boys than those that do not.
One of the statistics reported was that out of 565 births where
both
parents smoked more than a pack a day, 255 were boys. What
proportion
of these births resulted in a boy? Based on this proportion, find
a
95% confidence interval for the proportion of all births, where both
parents
smoke, that would result in a boy. (Stat
> Basic Statistics > 1 Proportion click on Summerized
data: and put in the appropriate numbers. It should default
to
use a 95% confidence interval. Also under Options... click on Use test and interval based on normal
distribution.)
Another statistic reported was that out of 3602 births where
both
parents did not smoke, 1975 were boys. What proportion of these
births
resulted in a boy? Based on this proportion, find a 95%
confidence
interval for the proportion of all births, where neither parent smoke,
that
would result in a boy.
Find the 95% confidence interval for the difference in the
proportion
of boys born to parents that do not smoke to those that do. Write a
sentence as to what your confidence interval is describing. (Stat > Basic Statistics > 2 Proportions then
click on Summarized data: and put the results for the
nonsmoking parents
in for the First sample: and the smoking parents in for the Second
sample:. Under Options..., click on not equal to for
the
alternative hypothesis to get a confidence interval.)