Management literature proposes that companies practicing Lean Manufacturing (a process management tool) should train their employees in statistical techniques. An independent, random sample of 160 companies was surveyed and asked about whether they use Lean Manufacturing (yes or no) and whether they train their employees in statistical techniques (yes or no). The results are summarized below:

	Yes, statistical training	No, statistical training
Yes, use Lean	50	30
No, do not use Lean	20	60

Question 1 What is the best point estimate for the true population proportion of companies that train their employees in statistical techniques if they use Lean Manufacturing.

Question 2 (multiple choice)

What is the 95% confidence interval for the true population proportion of companies that train their employees in statistical techniques if they use Lean Manufacturing? Use the normal approximation method.

a) (0.61, 0.82)

b) (0.52, 0.73)

c) (0.300, 0.455)

d) (0.24, 0.38)

Question 3

What is the margin of error associated with the above confidence interval? Use three decimal places.