Question

QUESTION 1

1. Solve the problem.
   
   A bank's loan officer rates applicants for credit. The ratings are normally distributed with a mean of 200 and a standard deviation of 50. If 40 different applicants are randomly selected, find the probability 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 nearest thousandth.
   
   50 people are selected randomly from a certain population and it is found that 13 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?

   		0.26
   		0.50
   		0.74
   		0.19

7.14286 points   

QUESTION 3

1. Use the confidence level and sample data to find a confidence interval for estimating the population μ. Round your answer to the same number of decimal places as the sample mean.
   
   A laboratory tested 83 chicken eggs and found that the mean amount of cholesterol was 233 milligrams with   milligrams. Construct a 95% confidence interval for the true mean cholesterol content, 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 size required to estimate an unknown population mean μ.
   
   How many women must be randomly selected to estimate the mean weight of women in one age group. We want 90% confidence that the sample mean is within 3.7 lb of the population mean, and the population 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 of 63.6 inches and a standard deviation of 2.5 inches. If 90 women are randomly selected, find the probability that they have a mean height between 62.9 inches and 64.0 inches.  ROUND TO 4 DECIMAL POSITIONS

7.14286 points   

QUESTION 6

1. Do one of the following, as appropriate: (a) Find the critical value z_α/2, (b) find the critical value t_α/2, (c) state that neither the normal nor the t distribution applies.
   
   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 construct a confidence interval for the population mean μ. Assume that the population 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 in class)
   
   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 critical value z_α/2, (b) find the critical value t_α/2, (c) state that neither the normal nor the t distribution applies.
   
   90%; n = 10; σ is unknown; population appears to be normally distributed.

   		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 construct a confidence interval for the population proportion p.
   
   A survey of 300 union members in New York State reveals that 112 favor the Republican candidate for governor. Construct the 98% confidence interval for the true population proportion of all New York 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 critical value z_α/2, (b) find the critical value t_α/2, (c) state that neither the normal nor the t distribution applies.
   
   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 of error E. Round your answer to the same number of decimal places as the 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 to estimate the population proportion.
   
   Margin of error: 0.04; confidence level: 95%; from a prior study,   is estimated by the decimal equivalent of 89%.

   		9
   		236
   		209
   		708

7.14286 points   

QUESTION 14

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

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

Answer 1

10)

Solution :

3 and 12 questions are incomplete. Please check.