Question

The company you work for produces automotive parts for GM. A certain machine that makes a cutout in a
piece of steel averages a cut size of 203.2085 mm with a standard deviation of 0.2083 mm. A random sample
of 66 is taken from the population. What is the distribution of the sample mean?
a. Approximately normal with mean 25.0132 and standard error 0.0256.
b. 68% of sample averages will fall between 203.0002 and 203.4168.
c. Approximately normal with mean 203.2085 and standard error 0.0256.
d. Approximately normal with mean 203.2085 and standard error 0.2083.

Answer 1

Ans:

sampling distribution of sample means will follow normal distribution with(as n>=30):

mean=203.2085

standard deviation=0.2083/sqrt(66)=0.0256

Approximately normal with mean 203.2085 and standard error 0.0256

Option c is correct.