(a). A consultancy firm checked the safety of a concrete dam and accepted the null hypothesis that the dam is safe. If it was later proved that it was unsafe, what type of error did the consultant commit?

(b). The performance of a computer is observed over a period of 2 years to check the claim that the probability is 0.20 and that its downtime will exceed 5 years in any given week. Testing the null hypothesis p =0.20 against the alternative hypothesis p 0.20 and what can we conclude at =0.05 if there were only 11 weeks in which the downtime of the computer exceeded 5 hrs?