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 7.2%.
a) Find the mean and standard deviation for the number of times this letter will be found on a typical page of 1900 characters.
b) In an intercepted message, a page of 1900 characters is found to have3 the letter occurring 169 times. Is this unusual?
a. Yes, because 169 is greater than the maximum usual value
b. Yes, because 169 is below the minimum usual value
c. Yes, because 169 is within the range of usual values
d. No, because 169 is within the range of usual values