You wish to estimate, with 97% confidence and within 3.5% of the true population, the proportion of computers that need repairs or have problems by...

You wish to estimate, with 97% confidence and within 3.5% of the true population, the proportion of computers that need repairs or have problems by the time the product is three years old.a) no prelimanary estimate is available. Find the minimum sample size neededb) Find the minimum sample size needed, using a prior study that found that 19% of computers needed repairs or had problems by the time the product was three years oldc) compare the results from parts (A)and (B)