Why are unbiased estimators preferred over biased estimators?

On any given day, the number of users, u, that access a certain website can be represented by the inequality 1125-4530 which of the following represents the range of users that access the website each day? u> 95 or u < 155 95> u> 155 u< 95 or > 155 95

Ivan and jeff buy a package of 8 pens for $4.00. ivan wants 5 of the pens, and jeff wants 3.how much should each student pay?

What set does not contain -3 the set of all real numbers the set of all integers the set of all whole numbers the set of all rational numbers