Criminologists have long debated whether there is a relationship
between weather conditions and the incidence of violent crime.
The author of the article “Is There a Season for Homicide?”
(Criminology, 1988: 287-296) classified 1361 homicides according
to season, resulting in the accompanying data. Test the null
hypothesis of equal proportions using α = 0.01.
Winter
328
Spring
334
Summer
372
Fall
327
The water diet requires one to drink two cups of water every half
hour from when one gets up until one goes to bed, but otherwise
allows one to eat whatever one likes. Four adult volunteers agree
to test the diet. They are weighed prior to beginning the diet and
after six weeks on the diet. The weights (in pounds) are
Before the diet
After the diet
180
170
125
130
240
215
150
152
For the population of all adults, assume that the weight loss after
six weeks on the diet (weight before beginning the diet minus
weight after six weeks on the diet) is Normally distributed with
mean µ. Run a test of significance to determine if the diet leads to
weight loss. (Set up the hypotheses, compute the statistic, find the
P-value, and conclude.) Use sinificance level 0.1 to conclude.
Each person in a random sample of 1100 “likely voters” (as
defined by a professionapolling organization) was questioned about
his or her political views. Of those surveyed, 708 felt that “the
economy’s state” was the most urgent national concern.
Each person in a random sample of 1100 “likely voters” (as
defined by a professionapolling organization) was questioned about
his or her political views. Of those surveyed, 708 felt that “the
economy’s state” was the most urgent national concern.
1. What is the sample proportion that felt the economy’s state
was the most urgent national concern?
Each person in a random sample of 1100 “likely voters” (as
defined by a professionapolling organization) was questioned about
his or her political views. Of those surveyed, 708 felt that “the
economy’s state” was the most urgent national concern.
1. What is the sample proportion that felt the economy’s state
was the most urgent national concern?
2. What is the standard error SE of , the sample proportion
viewing the economy’s state as most urgent?
Each person in a random sample of 1100 “likely voters” (as
defined by a professionapolling organization) was questioned about
his or her political views. Of those surveyed, 708 felt that “the
economy’s state” was the most urgent national concern.
1. What is the sample proportion that felt the economy’s state
was the most urgent national concern?
2. What is the standard error SE of , the sample proportion
viewing the economy’s state as most urgent?
3. Find a 99% confidence interval for the proportion p of all
likely voters that feel the economy’s state is the most urgent
national concern.