2. Compute the critical value z/2 that corresponds to a 96% level of confidence.

za/2=?

3. Determine the point estimate of the population proportion, the margin of error for the following confidence interval, and the number of individuals in the sample with the specified characteristic, x, for the sample size provided. Lower bound=0.336, upper bound=0.654, n=1200

The point estimate of the population proportion is______. (Round to the nearest thousandth as needed.)

The margin of error is______.(Round to the nearest thousandth as needed.)

The number of individuals in the sample with the specified characteristic is ______. (Round to the nearest integer as needed.)

5. A national survey of 2500 adult citizens of a nation found that 25% dreaded Valentine's Day. The margin of error for the survey was 13.8 percentage points with 85% confidence. Explain what this means.

Which statement below is the best explanation?

A. There is 85% confidence that 25% of the adult citizens of the nation dreaded Valentine's Day.

B. There is 85% confidence that the proportion of the adult citizens of the nation that dreaded Valentine's Day is between 0.112 and 0.388.

C. There is 71.2% to 98.8% confidence that 25% of the adult citizens of the nation dreaded Valentine's Day.

D. In 85% of samples of adult citizens of the nation, the proportion that dreaded Valentine's Day is between 0.112 and 0.388.

9. Determine the t-value in each of the cases.

Find the t-value such that the area left of the t-value is 0.005 with 15 degrees of freedom. [Hint: Use symmetry.]

10. A simple random sample of size n is drawn. The sample mean, x, is found to be 18.1, and the sample standard deviation, s, is found to be 4.3. If the sample size is 17, what conditions must be satisfied to compute the confidence interval?

A.

The sample size must be large and the sample should not have any outliers.

B.

The sample data must come from a population that is normally distributed with no outliers.

C.

The sample must come from a population that is normally distributed and the sample size must be large.