posted by Ashley .
A survey found that 25% of pet owners had their pets bathed professionally rather than doing it themselves. If 20 pet owners are randomly selected find the probability that between 12 and 7 pet owners, inclusive, have their pets bathed professionally.
Try the binomial probability function. If you have access to a binomial probability table, this will make the problem much easier to solve.
In most tables, you need to find x, n, and p. You will need to find each x value, then add together for your total probability. x = 7, 8, 9, 10, 11, 12. n = 20 and p = .25 for your other values.
I hope this will help.