The table shows the results of a survey in which separate samples of 400 adults each from theEast, South,Midwest, and West were asked if traffic congestion is a serious problem in their community. Complete parts(a) and(b).

a) The95% confidence interval for the proportion of adults from the West who say traffic congestion is a serious problem is _,_

b. Construct a95% confidence interval for the proportion of adults from the Midwest who say traffic congestion is a serious problem.

The95% confidence interval for the proportion of adults from the Midwest who say traffic congestion is a serious problem is _,_

East-36%

South-32%

Midwest-27%

West-57%

2.Assume the random variable x is normally distributed with mean u=50 and standard deviation o=6. Fidn the indicated probality P(x>42)=

3.In a survey of 3419 adults, 1407 say they have started paying bills online in the last year.

Construct a99% confidence interval for the population proportion. Interpret the results.

With99% confidence, it can be said that the sample proportion of adults who say they have started paying bills online in the last year is between the endpoints of the given confidence interval.

B.

The endpoints of the given confidence interval show that adults pay bills online99% of the time.

C.

With99% confidence, it can be said that the population proportion of adults who say they have started paying bills online in the last year is between the endpoints of the given confidence interval.

4.A population has a mean =71 and a standard deviation equal 28. Find the mean and standard deviation of a sampling distribution of sample means with sample size =49

ux=

ox=

5.Construct the indicated confidence interval for the population mean using at-distribution.

c=.98 x=107 s=10 n=15

6.A researcher wishes toestimate, with 95% confidence, the population proportion of adults who are confident with theircountry's banking system. His estimate must be accurate within 3% of the population proportion.

(a) No preliminary estimate is available. Find the minimum sample size needed.

(b) Find the minimum sample sizeneeded, using a prior study that found that 32% of the respondents said they are confident with theircountry's banking system.

(c) Compare the results from parts (a) and (b).

a)what is the minimum sample size needed assuming that no prior information is available? n=

b) What is the minimum sample size needed using a prior study that found that 32% of the respondents said they are confident with theircountry's bankingsystem? n-

c)How do the results from a to b compare