The principal at Riverside High School would like to estimate the mean length of time each day that it takes all the buses to arrive and unload the students. How large a sample is needed if the principal would like to assert with 90% confidence that the sample mean is off by, at most, 7 minutes. Assume that s14 minutes based on previous studies.

A. 10

B .7

C. 12

D.. 11

In a random sample of 31criminals convicted of a certain crime, it was determined that the mean length of sentencing was 65months, with a standard deviation of 13months. Construct and interpret a 90 % confidence interval for the mean length of sentencing for this crime.

(Use ascending order. Round to one decimal place as needed.)

A.

There is a % probability that the mean length of sentencing for the crime is between

nothing and

nothing months.

B.

% of the sentences for the crime are between

nothing and

nothing months.

C.

We can be % confident that the mean length of sentencing for the crime is between

nothing and

nothing months.

Determine (a) the point estimate of the population proportion, (b) the margin of error for the associated confidence interval, and (c) the number of individuals in the sample with the specified characteristic, x, for the sample size provided.

Lower bound 0.199, upper bound 0.451, n= 1200

(a) The point estimate of the population proportion is ________.

(b) The margin of error for the confidence interval is _______.

(c) The number of individuals in the sample with the specified characteristic is ______.

A random sample ofadults 1011 in a certain large country was asked "Do you pretty much think televisions are a necessity or a luxury you could do without?" Of the 1011adults surveyed,516 indicated that televisions are a luxury they could do without.

Construct and interpret a 95 % confidence interval for the population proportion of adults in the country who believe that televisions are a luxury they could do without. Select the correct choice below and fill in any answer boxes within your choice.

(Type integers or decimals rounded to three decimal places as needed. Use ascending order.)

A.

There is a _____% chance the proportion of adults in the country who believe that televisions are a luxury they could do without is between

nothing and

nothing.

B.

We are

nothing% confident the proportion of adults in the country who believe that televisions are a luxury they could do without is between

nothing and

nothing.

Determine the point estimate of the population mean and margin of error for the confidence interval.

Lower bound is 21 , upper bound is 29 .

The point estimate of the population mean is

_______.

The margin of error for the confidence interval is

_______.

Assume that blood pressure readings are normally distributed with a mean of 116and a standard deviation of 4.8 . If 36people are randomly selected, find the probability that their mean blood pressure will be less than 118 . Round to four decimal places.