(a) A survey conducted by a pharmaceutical company found that the probability of success in the clinical trial is 0.75. Suppose five hundred clinical trials are performed in the study, what is the probability of succeeding in the clinical trial between 290 and 430 times? Use normal approximation of the binomial distribution. ...............................................................

(b) A local motel found that 395 out of 800 customers cancelled their accommodation bookings after they had reserved their accommodation. At 0.01 level of significance, is there evidence that the population proportion of customers who reserve their accommodation and cancel their bookings is less than 0.45? ............................................................................................................ 

(c) The owner of a butcher shop wants to estimate the mean amount that customers spend on their purchase on weekdays. Find the 95% confidence interval estimate of the mean given the following random sample of $80, $84, $95, $65, $131, $110, $118, $105, $123.......................