A bank manager wants to know the mean amount of mortgage paid per month by homeowners in an area. a random sample of 105 homeowners selected from this area showed that they pay an average of $1450 per...

Extracted text: A bank manager wants to know the mean amount of mortgage paid per month by homeowners in an area. a random sample of 105 homeowners selected from this area showed that they pay an average of $1450 per month for their mortgages. The population standard deviation of such mortgages is $200. a. Find a 98 % confidence interval for the mean amount of mortgage paid per month by all homeowners in this area. The confidence interval is b. Suppose the confidence interval obtained in part a is too wide. How can the width of this interval be reduced? Consider all possible alternatives. Which alternative is the best? (This part is for you to think about and no answer needs to be submitted.) Note 1: Your confidence interval should be given in the format of (a, b) where a and b are two numbers. Note 2: Keep 2 decimal places in your answer for the confidence interval.