Problem $4$S$-16$ An office manager has received a report from a consultant that includes a section on equipment replacement. The report indicates that scanners have a service life that is normally distributed with a mean of $54$ months and a standard deviation of $6$ months. On the basis of this information, determine the proportion of scanners that can be expected to fail in the following time periods: Use Table A and Table B$.$ a$.$ Before $46$ months of service. $($Round z values to $2$ decimal places, probability calculations to $4$ decimal places and your final answer to $4$ decimal places.$)$ Proportion of scanners $<46$ b$.$ Between $52$ and $57$ months of service. $($Round z values to $2$ decimal places, probability calculations to $4$ decimal places and your final answer to $4$ decimal places.$)$ T Proportion of scanners $52$