The scores of students on the ACT college entrance examination in 2001 had mean =21.0 and standard deviation = 4.7. The distribution of scores is only roughly normal. Now take an SRS of 50 students who took the ACT test.

What is the probability that the mean score, , of these 50 students is 23 or higher? (Round answer to the nearest ten-thousandth, the fourth decimal place.)