Timmy recorded the number of
cricket chirps he heard in a minute on several different nights. He recorded
the number of chirps, x, that he heard during each recording. The number of
chirps observed was normally distributed with a mean of 54 and a standard
deviation of 8.4.
Find the probability of observing
at most 64 chirps during a survey. Round your answer to the nearest thousandth
(using a z score rounded to the nearest tenth).