Question

The interest rates paid by 30 financial institutions on a certain day for money market deposit accounts are shown in the accompanying table.

Rate %	2	2.25	2.55	2.56	2.58	2.60	2.65	2.85
Institutions	2	6	9	1	1	7	2	2

Let the random variable X denote the interest rate per year paid by a randomly chosen financial institution on its money market deposit accounts.

(a) Find the probability distribution associated with these data. (Round your answers to three decimal places.)

Rate %		P(X = x)
2
2.25
2.55
2.56
2.58
2.60
2.65
2.85

(b) Find the probability that the interest rate paid by a financial institution chosen at random is less than 2.56% per year. (Round your answer to three decimal places.)

Answer 1

a)dividing each frequency with n=30 :

Rate %	P(X=x)
2	0.067
2.25	0.200
2.55	0.300
2.56	0.033
2.58	0.033
2.60	0.233
2.65	0.067
2.85	0.067

b) probability that the interest rate paid by a financial institution chosen at random is less than 2.56% per year =(9+6+2)*100/30=0.567