The quarterly returns for a group of 72 mutual funds with a mean of 2.9% and a standard deviation of 4.2% can be modeled by a Normal model. From these funds, nd the cutoff return value{s} that would separate the a) highest 20%. b) lowest 30%. c) middle 80%. d) highest 70%. a) Select the correct choice and ll in any answer boxes in your choice below. (Round to two decimal places as needed.) OA. x> % OB. x % OB. X