Q1) Clean-up crew of medium-sized firm has the average clean-up time of 72.0 total hours with variance of 64 hours squared. Clean-up times are bell-shaped.
(a) What proportion of time will it take clean-up crew 56 or more hours for cleaning plant?
(b) 95% of time the total clean-up time will fall within what interval about mean?
Define the lower and upper limits of interval.
Q2) What occurs to variance of given set of scores if each original score is
(a) Tripled?
(b) Increased by 15 points?
Provide the answer in terms of any percentage increase. Answer the problem empirically.