Mete

Calculate the probability that 3 or fewer rainy days occur during the next 15 days. The probability any day is rainy is .2. For this question I tried using binomial distribution by setting x = 0, 1, 2, 3. p=.2 and n =15. After doing all of them, Do add th...

A normal distribution has a mean = 100. Find its standard deviation if 17% of the values exceed 144. All I can say is wow. Book is of no help. Neither is teacher. Can anyone help?

The mean price of purchases is $110 and the standard deviation = $12. What is the probability of a purchase exceeding $90? I need help reviewing. Please give some input.