The Central Intelligence Agency (CIA) has specialists who analyze the frequencies of letters of the alphabet in an attempt to decipher intercepted messages. In standard English text, the letter r is used at a rate of 7.58%.

Find the mean and standard deviation for the number of times the letter r will be found on atypical page of 2200 characters.
(Round answer to one decimal place.)
$\displaystyle \mu=$
(Round answer to two decimal places.)
$\displaystyle \sigma=$

Give the interval of usual values for the number of r's appearing on a page of 2200 characters.
(Enter answer as an interval using square-brackets only with whole numbers.)
usual values =

In an intercepted message sent to a foreign country, a page of 2200 characters is found to have the letter r occurring 167 times. Is this unusual?