Question 1

1. Assume that a sample is used to estimate a population proportion p. Find the margin of error E that corresponds to the given statistics and confidence level. Round the margin of error to four decimal places. 98% confidence; the sample size is 800, of which 40% are successes

   A.

   0.0339

   B.

   0.0446

   C.

   0.0403

   D.

   0.0355

1 points  

Question 2

1. Find the value of that corresponds to a confidence level of 91%.

   A.

   1.75

   B.

   1.34

   C.

   1.645

   D.

   1.70

1 points  

Question 3

1. Find the appropriate critical value for the following:  99% confidence level ; n = 17; ? is unknown; population appears to be normally distributed.

   A.

   z?/2 = 2.567

   B.

   z?/2 = 2.583

   C.

   t?/2 = 2.898

   D.

   t?/2 = 2.921

2 points  

Question 4

1. Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p. n = 195, x = 162; 95% confidence

   A.

   0.788 < p < 0.873

   B.

   0.777 < p < 0.884

   C.

   0.789 < p < 0.873

   D.

   0.778 < p < 0.883

1 points  

Question 5

1. Thirty randomly selected students took the calculus final. If the sample mean was 95 and the standard deviation was 6.6, construct a 99% confidence interval for the mean score of all students.

   A.

   92.03 < ? < 97.97

   B.

   92.95 < ? < 97.05

   C.

   91.68 < ? < 98.32

   D.

   91.69 < ? < 98.31

1 points  

Question 6

1. 50 people are selected randomly from a certain population and it is found that 12 people in the sample are over 6 feet tall. What is the point estimate of the proportion of people in the population who are over 6 feet tall?

   A.

   0.18

   B.

   0.76

   C.

   0.24

   D.

   0.50

2 points  

Question 7

1. Use the given data to find the minimum sample size required to estimate the population proportion. Margin of error: 0.028; confidence level: 99%; and unknown

   A.

   2223

   B.

   2115

   C.

   1116

   D.

   1939