D$.$ Consider the following repair data: $(2$ point each$)$ Month No$.$ of units in the field No$.$ of units returned No$.$ of units repaired $($failed$)$ January $300,0001200650$ February $400,0001250700$ March $500,0002400725$ a$.$ Over the three$-$month period, what was the average number of units in the field? b$.$ Over the three$-$month period, what was the return rate and failure rate? c$.$ What is the estimated annual return rate and annual failure rate? d$.$ If the product had a contractual limit of $5\%$ annual failure rate, is the product past the limit$?$ e$.$ What is the ratio of failures to returns? f$.$ Look at the number of units returned. Is there a trend that is noteworthy? g$.$ Compare the trend of units returned to the trend of units repaired. What conclusions do you draw?