Q The clothes selling out follow a normal distribution. and each cloth is independent. a ). According to the recording , the expected standard deviation is at most 30cm. Assuming it is exact SD, what is the min number of cloth that would need to be sampled to determine the average doth yield with a margin of error of at least I i'm at 98% confidence level ? b) If I get 8 clothes, and the sample mean is 692 a. According to the SD in a ) determine a 98% confidence interval for a mean cloth. ( If you can explain the interval, I will understand it easier ' )