# Confidence interval for mean help

1. To help consumers assess the risks they are taking, the food and drug administration publishes the amount of nicotine found in all commercial brands of cigarettes. A new cigarette has recently been marketed. The FDA tests on this cigarette gave a mean nicotine of content 28.2 milligrams and standard deviation of 2.7 milligrams for a sample of n = 9. The FDA claims that the mean nicotine content exceeds 32.2 milligrams for this brand of cigarette, and their stated reliability is 99%. Do you agree

1. no, since the value 32.2 does fall in the 99% confidence interval

2. yes, since the value 32.2 does not fall in the 99% confidence interval

3.no since the value 32.2 does not fall in the 99% confidence interval

4. yes, since the value 32.2 does fall in the 99% confidence interval

2. A confidence interval was used to estimate the proportion of statistics students that are female. A random sample of 72 statistics students generated the following 99% confidence interval. State the confidence level used to create the confidence interval.

1. between 43.8% and 64.2%

2. 99%

3. 64.2%

4. 72%

3. A survey claims that 9 out 0f 10 doctors (i.e 90%) recommend brand z for their children. To test this claim against the alternative that the actual proportion of doctors who recommend brand Z is less than 90%, a random sample of doctors was taken. Suppose the test statistic is z = -1.95. can we conclude that Ho should be rejected at the a) a = 0.10 b) a = 0.05 and C) 0.01 level?

a. a)no b)yes c)yes

b. a)yes b)yes c)no

c. a)yes b)yes c)yes

d. a)no b)no c)no

#### Solution Summary

The solution gives the details of construction of confidence interval for mean and proportion.