Note: this is a multi-part . once an answer is submitted, you will be unable to return to this part determine whether the relation on the set of all people is reflexive, symmetric, antisymmetric, and/or transitive, where (a. b) e rif and only if ind b have a common grandparent. (check all that apply) reflexive symmetric transitive antisymmetric

1. according to the internal revenue service, the mean tax refund for the year 2007 was $2,708. assume the standard deviation is $650 and that the amounts refunded follow a normal probability distribution. a. what percent of the refunds are more than $3,000? b. what percent of the refunds are more than $3,000 but less than $4,000? c. what percent of the refunds are less than $2,000?