Write the null and alternative hypotheses to test each of the following situations. a) an online electronics store is concerned about the timeliness of the delivery of their products. the vp of operations and marketing recently stated that she wanted the percentage of products delivered on time to be greater than 92%, and she wants to know if the company has succeeded. b) a realty company recently announced that the proportion of houses taking more than four months to sell is now less than 57%. c) a financial firm's accounting reports have an accuracy rate above 99%.