Download Practice final Math 12 Fall 2013 Please show all work. Are low

Practice final Math 12 Fall 2013
Please show all work.
1. Are low-fat diets or low-carb diets more effective for weight loss? A sample of 80 subjects went on a
low-carbohydrate diet for six months. At the end of that time, the sample mean weight loss was 11.5
pounds with a sample standard deviation of 7.17 pounds. A second sample of 75 subjects went on a
low-fat diet. Their sample mean weight loss was 17.9 with a standard deviation of 6.75. Can you
conclude that the mean weight loss differed between the two diets? Use the α = 0.05 level.
2. A study reported that in a sample of 81 men, 25 had elevated total cholesterol levels (more than 200
milligrams per deciliter). In a sample of 99 women, 34 had elevated cholesterol levels.
Can you conclude that the proportion of people with elevated cholesterol levels differs between men and
women? Use the α = 0.01 level of significance.
3. In an experiment to determine whether there is a systematic difference between the weights obtained
with two different mass balances, six specimens were weighed, in grams, on each balance. The
following data were obtained:
The null hypothesis is that the weights given by the two scales is the same. Test at the 2% significance
level if there is a systematic difference between the weights obtained with the two different balances.
4. The number of visits to a certain web site were counted each day of a particular week. The results are
given in the following table.
Test the hypothesis that web site visits are equally likely to occur on any day of the week. (Hint: Each
day of the week will have the same percentage of the weekly visits.) Use the α = 0.01 level of
significance.
5. A sample of 146 university students who recently moved off-campus were polled to see whether they
agree that off-campus living is preferable to on-campus living. In addition, each was asked how many
people live in their current off-campus residence. The results are summarized in the following
contingency table.
Perform a test for independence, using the α = 0.05 level of significance. What do you conclude?
6. The Australian sheep dog is a breed renowned for its intelligence and work ethic. It is estimated that
45% of adult Australian sheep dogs weigh 65 pounds or more. A sample of 15 adult dogs is studied.
What is the probability that more than 12 of them weigh 65 lb or more?
7.
A bottler of drinking water fills plastic bottles with a mean volume of 993 milliliters (mL) and standard
deviation 6 ml. The fill volumes are normally distributed. What proportion of bottles have volumes
between 991 ml and 997 ml?