QUESTION 1

1. Solve the problem.
   
   A bank's loan officer rates applicants for credit. The ratings arenormally distributed with a mean of 200 and a standard deviation of50. If 40 different applicants are randomly selected, find theprobability that their mean is above 215.

   		0.4713
   		0.3821
   		0.0287
   		0.1179

7.14286 points   

QUESTION 2

1. Solve the problem. Round the point estimate to the nearestthousandth.
   
   50 people are selected randomly from a certain population and it isfound that 13 people in the sample are over 6 feet tall. What isthe point estimate of the proportion of people in the populationwho are over 6 feet tall?

   		0.26
   		0.50
   		0.74
   		0.19

7.14286 points   

QUESTION 3

1. Use the confidence level and sample data to find a confidenceinterval for estimating the population μ. Round your answer to thesame number of decimal places as the sample mean.
   
   A laboratory tested 83 chicken eggs and found that the mean amountof cholesterol was 233 milligrams with   milligrams.Construct a 95% confidence interval for the true mean cholesterolcontent, μ, of all such eggs.

   		229 mg < μ < 236 mg
   		229 mg < μ < 235 mg
   		231 mg < μ < 237 mg
   		230 mg < μ < 236 mg

7.14286 points   

QUESTION 4

1. Use the given information to find the minimum sample sizerequired to estimate an unknown population mean μ.
   
   How many women must be randomly selected to estimate the meanweight of women in one age group. We want 90% confidence that thesample mean is within 3.7 lb of the population mean, and thepopulation standard deviation is known to be 28 lb.

7.14286 points   

QUESTION 5

1. Solve the problem.
   
   Assume that women's heights are normally distributed with a mean of63.6 inches and a standard deviation of 2.5 inches. If 90 women arerandomly selected, find the probability that they have a meanheight between 62.9 inches and 64.0 inches.  ROUND TO 4DECIMAL POSITIONS

7.14286 points   

QUESTION 6

1. Do one of the following, as appropriate: (a) Find the criticalvalue z_α/2, (b) find the critical value t_α/2,(c) state that neither the normal nor the t distributionapplies.
   
   90%; n =9; σ = 4.2; population appears to be very skewed.

   		Neither the normal nor the t distribution applies.
   		zα/2 = 1.645
   		zα/2 = 2.306
   		tα/2 = 1.860

7.14286 points   

QUESTION 7

1. Use the given degree of confidence and sample data to constructa confidence interval for the population mean μ. Assume that thepopulation has a normal distribution.
   
   n = 30,   = 83.1, s = 6.4, 90% confidence

   		81.13 < μ < 85.07
   		81.11 < μ < 85.09
   		80.71 < μ < 85.49
   		79.88 < μ < 86.32

7.14286 points   

QUESTION 8

1. Find the indicated critical z value (use the table given inclass)
   
   Find the critical value z _α/2 that corresponds to a 94%confidence level.

7.14286 points   

QUESTION 9

1. Do one of the following, as appropriate: (a) Find the criticalvalue z_α/2, (b) find the critical value t_α/2,(c) state that neither the normal nor the t distributionapplies.
   
   90%; n = 10; σ is unknown; population appears to be normallydistributed.

   		Neither the normal nor the t distribution applies.
   		tα/2 = 1.812
   		zα/2 = 1.645
   		tα/2 = 1.833

7.14286 points   

QUESTION 10

1. Use the given degree of confidence and sample data to constructa confidence interval for the population proportion p.
   
   A survey of 300 union members in New York State reveals that 112favor the Republican candidate for governor. Construct the 98%confidence interval for the true population proportion of all NewYork State union members who favor the Republican candidate.

   		0.304 < p < 0.442
   		0.301 < p < 0.445
   		0.308 < p < 0.438
   		0.316 < p < 0.430

7.14286 points   

QUESTION 11

1. Do one of the following, as appropriate: (a) Find the criticalvalue z_α/2, (b) find the critical value t_α/2,(c) state that neither the normal nor the t distributionapplies.
   
   91%; n = 45; σ is known; population appears to be very skewed.

   		Neither the normal nor the t distribution applies.
   		tα/2 = 1.34
   		zα/2 = 1.70
   		tα/2 = 1.645

7.14286 points   

QUESTION 12

1. Use the confidence level and sample data to find the margin oferror E. Round your answer to the same number of decimal places asthe sample mean unless otherwise noted.
   
   College students' annual earnings in dollars: 99%confidence;      

   		196
   		233
   		258
   		891

7.14286 points   

QUESTION 13

1. Use the given data to find the minimum sample size required toestimate the population proportion.
   
   Margin of error: 0.04; confidence level: 95%; from a priorstudy,   is estimated by the decimal equivalent of89%.

   		9
   		236
   		209
   		708

7.14286 points   

QUESTION 14

1. Use the given data to find the minimum sample size required toestimate the population proportion.
   
   Margin of error: 0.005; confidence level:97%;   and   unknown

   		47,089
   		37,127
   		46,570
   		47,180