The Bank of Connecticut issues Visa and MasterCard credit cards. It is estimated
ID: 3336694 • Letter: T
Question
The Bank of Connecticut issues Visa and MasterCard credit cards. It is estimated that the balances on all Visa credit cards issued by the Bank of Connecticut have a mean of $ 835 and a standard deviation of $ 265 . Assume that the balances on all these Visa cards follow a normal distribution.
a. What is the probability that a randomly selected Visa card issued by this bank has a balance between $ 1100 and $ 1420 ? Round your answer to three decimal places.
P = _____
b. What percentage of the Visa cards issued by this bank have a balance of $ 735 or more? Round your answer to two decimal places.
P =_____ %
Explanation / Answer
Mean is 835 and standard deviation s is 265. z is defined as (x-mean)/s
a) P(1100<x<1420)=P((1100-835)/265<z<(1420-835)/265)=P(1<z<2.21) or P(z<2.21)-P(z<1)
from normal distribution table we get 0.8869-0.8413 =0.0456
b) P(x>735)=P(z>(735-835)/265)=P(z>-0.38) or 1-P(z<0.38) . from normal table we get 1-0.6480 =0.352 or 35.2%
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