Day$12346$DJIA$13,010\mathrm{.}0013,100\mathrm{.}0013,165\mathrm{.}0013,080\mathrm{.}0013,070\mathrm{.}0013,150\mathrm{.}00$Day$7101112$DJIA$13,220\mathrm{.}0013,130\mathrm{.}0013,250\mathrm{.}0013,315\mathrm{.}0013,240\mathrm{.}0013,310\mathrm{.}00$a$)$ Calculate a four$-$day moving average for Days $4$ through $9.$ Assume that the index on Day $13$closes at $13,300.$ Would this signal a buy or sell decision?b$)$ With this value for Day $13,$ the four$-$day moving average would be