Question

15. Men average 5’10” in height, with a standard deviation of 2”. If we take x-bars from groups of 10 men, what would be the average and standard deviation of x-bar?     

a. 70, 0.2

b. 70, 0.63

c. 22.1, 0.2

d. 22.1, 0.63

28. An invoice has 7 different defects that it can contain. 400 invoices are checked and 80 defects are found. The DPU is            

a. 80 / 400

b. 80 / (400 x 7)

c. 400 / 80

d. 80 / 7

29. An invoice has 7 different defects that it can contain. 400 invoices are checked and 80 defects are found. The defects per opportunity (DPO) is     

a. 80 / 400

b. 80 / (400 x 7)

c. 400 / 80

d. 80 / 7

30. A large population is known to have a mean of 53 and a standard deviation of 5. 100 random samples, each of size 16, are selected. According to the Central Limit Theorem, the distribution of the 100 sample means has a mean of approximately                    

a. 53

b. 53 / SQRT(16)

c. 53 / SQRT(100)

d. 53 / SQRT(5)

31. For the regression line y = 12.2 + 7.8 x, 7.8 is the               

a. correlation coefficient

b. r-squared

c. intercept

d. slope

Answer 1

Solution-

15. There is no sample data provided in the question. Since X bar is the average of the sample, and average of the population is mentioned here as 5'10" which is 5*12 + 10 = 70 inches, we can say that X bar of 10 sample would also be the same as average of the population. which is 70 inches. Same goes for the standard deviation.

Therefore answer is 70, 0.2

16. DPU or defects per unit = Total number of defects/ total number of units = 80/400

17. Number of opportunities, 0= 7

Total units, U = 400

Total defects = 80

Defects per opportunity = D/(U*O) = 80/(400*7) which is the option B.

30. Central limit theorem states that if we take sufficiently large samples from a population then the mean of sample is equal to the mean of the population. Therefore mean of the 100 sample distribution is equal to the mean of population which is 53. So option A is correct.

31. 7.8 is known as the slope