A bank manager wants to know the mean amount of mortgage paid per month by homeowners in an area. A random sample of 110 homeowners selected from this area showed that they pay an average of $1580 per month for their mortgages. The population standard deviation of such mortgages is $208. a. Find a 95% confidence interval for the mean amount of mortgage paid per month by all homeowners in this area. Round your answers to two decimal places. to dollars b. Suppose the confidence interval obtained in part a is too wide. Select all of the ways the width of this interval can be reduced. O Increasing the confidence level O Lowering the confidence level O Lowering the sample size O Increasing the sample size