In this problem. The percentage change in a rich market share Byron is given which be happy, noting the X for four tests cities at four control cities. In first caution, the had befriended me off the change in market ship for the fourth test cities. To find them me, we will require the summer fall X values for the best cities that this plus 18 plus 15 last seven blasting because it quite so 50. So our submission eggs for the Death Cities is 50 and therefore me expert is equal to summation X that this 50 divided by end which is four, and there are four test cities. So this is equal group 12.5 that this the mean off the change in market share for the four test cities is 12.5. In the next part, we have to find the mean off the changing market ship 44 control cities. For that be the required information x 44 control cities which is plus one minus eight minus pi plus zero, which is equal to minus 12 that this summation x 44 control cities is equal to minus 12 and therefore meaning equal to summation X that this minus trail divided by end that this four as there are four controlled cities So I mean is it will do minus three. That this the mean off the changing market shed for the four control cities is minus three. In the next part, we have to find a stand that aviation off the change in market ship for the best cities. For that to be very quiet X square and its summation. So we will find the square off each x value. It didn't square, is it? While you treat, drink before 15 square is to 25. So that square is 49 and that square this 100. So the sound off on X travel used the estimation X squared is it Will do 6 98. Now we first find debate yet 44 test cities by using the formula X ray s square required to summation X squared, which we have found to be well to 6 98 minus. And that this foot, my dear, like my ex Bob Square, that doesn't mean for the test cities which we have found to be well do 12.5. We have to take its square, so it will be well going. Five squid divided by n minus one as any well before. And my husband is four minus one. That this tree therefore variance est square is equal. Do grant before 0.33 Now, as little sent activation s is equal to another rude as square so s is equal to another mood drank before point 33 which is sick. Well, do four point name. Therefore the standard deviation off the change in market share for the test cities is four point name in the next question being asked if I understand that aviation off the changing market ship for the control cities. For that we define summation X script for the control cities. But square is one minus X squared is 64 minus five square is 25 and zero square is zero. So the square for X credible used the sum of all X squared venues that this summation X squared isn't going to do 90 Dimension X squared is equal. Dude, I d so as square. Is it going to summation X quit that this 90 minus and we just four my name like by ex script their ex My divide Rex Bath script When experienced in me for the controls it this which we have found to be quite so minus three. So it would be my nested e squid divided by end minus one. Our anything well before so n minus one is equal to three. Therefore, Radiance s squared is equal Do anything and so standard A nation s is equal to another route as square which is equal to another route 18 and it is a choir do four going to do that? This the standard deviation off the changing market ship for the control cities is 4.2 now in the next kosher it this asked to find them difference between it means off parks in and be the mean which we have found in part A is 12.5 as we have to take the difference. Well, it's a threat. Did me founding the part B This minus three. So we this object minus three. So this is it Will do. Do I find five? Blustery beach is equal to 15.5. That this the estimate off the post sex change in sales due to the pre mia is 15.5 now in the next part of this given dead. The two standard deviations, which we have found but used to calculate an editor off. Bless my nurse. 7.95 This this amount of better we have to find this more less and now just estimate off the increase in sales. The smallest has to make that this is the lowest estimate can be from by taking this estimate, which were found in Park E that this 15.5 minus dick Even better that this 7.95 So this is it will do 7.55 and the land just estimate or the highest estimate can be found by taking this 15.5 last 7.95 the Jessica want to 23 point full five, so this more less estimate is 7.55 And Villa just estimated 23.45