Question

Bobby has a girlfriend, and wants to buy her a dozen roses. However, Bobby is cheap! He doesn't want to overpay for the flowers. He'd like to know what the average price is for a dozen roses. He decides to call around to 20 different florists and asks for their price of a dozen roses. But before Bobby begins to calculate a confidence interval to determine a range of values for the average price of a dozen roses, he thinks back to his Statistics class, and realizes that he cannot conduct the confidence interval. And it's not because he lost his calculator (in other words, he is certainly capable of doing the calculations).
In several complete sentences, explain why Bobby cannot conduct the confidence interval.

Answer 1

The assumptions for building a confidence interval for true mean are :-

Sample should come from a normal population

Sample should be random ( that is random selection of observations with equal probability )

First of all, Bobby called 20 different flourists, here assumption of random sample gets violated

Moreover, there may not be enough flourists in the area such that prices of dozen flowers form a normal population

Moreover alpha is not fixed yet,

So, if the assumptions are not wet results can be absurd