In a random sample of 30 manufacturing companies with fixed assets below $10,000, they obtained average profits of 1.8% with a standard deviation of 0.4%. In another randomly selected sample of 40 manufacturing companies with fixed assets between $10,000 and $50,000, the average earnings and their standard deviation were 2.4% and 0.6%, respectively.
a) With a significance of 0.05, can it be said that the
difference in mean utilities is equal to steel?
b)What is required to assume about the behavior of these
variables?