The Bank of Connecticut issues Visa and MasterCard credit cards. It is estimated
ID: 3337328 • 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 $840 and a standard deviation of $270. 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 $900 and $1440?
Round your answer to three decimal places.
b. What percentage of the Visa cards issued by this bank have a balance of $730 or more?
Round your answer to two decimal places.
Explanation / Answer
Mean is 840 and s is 270. z is given as (x-mean)/s
a) P(900<x<1440)= P((900-840)/270<z<(1440-840)/270)=P(0.22<z<2.22) =P(z<2.22)-P(z<0.22). from normal distribution table we get 0.9868-0.5871=0.3997
b) P(x>730)=P(z>(730-840)/270)=P(z>-0.41) or P(z<0.41)=0.6591
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