1. Suppose a 95% confidence interval is computed for u resulting in the interval (112.4, 121.6). Then it would be accurate to say
a. 95% of the time, u falls within the interval (112.4, 121.6)
b. There is a 95% chance that u will fall within the interval (112.4, 121.6)
c. We are 95% confident the interval (112.4, 121.6), captures u.
d. 95% of all the possible values for u fall within the interval (112.4, 121.6)
2. A piece of clothing takes an average of 38 minutes to move through an assembly line. If the standard deviation is 4 minutes, and the distributiion is normal, what is the probability that a piece of clothing will take over 45 minutes?
a. .040
b. .080
c. .175
d. .227
3. Suppose the random variable X has a normal distribution with a mean of 9.0 and variance of 49. The probability of X takes on a value of no more than 18 is approximately equal to
a. .0993
b. .4015
c. .9007
d. none of the answers