How many diferrent 9-letter words (real or imaginary) can be formed from the letters in the word economics?
the ans. must be 90,720

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $32.09. find the probability that a randomly selected bill will have an amount greater than $155, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?

What is the difference between the predicted value and the actual value

Mrs. gehrke said cheddar weighs 16.8 pounds. he actually weighs 15.2 pounds. what is the percent error?