Miscellaneous practical and theoretical questions (30%)a)     Assume you have observed 30 shops during a day and found that average sales is 2000 and known sample variance is 1200, respectively. Find 99% confidence interval for the population average of the sales. (8%)b)    One of the Manager in the Shop advise us CEO to to use 88% confidence interval instead of 99% for the population mean. Provide comments on result you found and compare it with the result in part c). (10%)c)     Explain what is meant by “Unbiased” and “Efficient” estimator. Give an example of each when you provide your answer. (6%)d)    Define Central Limit Theorem and Law of Large Numbers in your own words and also referring to the discussions we made in class (6%)data; [7 4 3 6 5 5 6 7 6 6 4 6 3 5 5 4 4 6 7 6 0 7 6 8 5 6 6 5 6 5]YOU HAVE ONLY 30 MINUTES !!!!In all answers show your calculations (Except variance calculation in question 1. But full points will be given to the correct answer).  I need well explained answer !!!!