A government agency has specialists who analyze the frequencies of letters of the alphabet in an attempt to decipher intercepted messages. In standard English text, a particular letter is used at a rate of 6.9%.
a. Find the mean and standard deviation for the number of times this letter will be found on a typical page of 2900 characters.
b. In an intercepted message, a page of 2900 characters is found to have the letter occuring 234 times. Is this unusual?