Q1) A major credit card company has find out that its customers charge average of $ 280 per month on their accounts with standard deviation o f$20

i) What percentage of customers charges more than $275 per month?

ii) What percentage of customers charges more than $43 per month?

iii) What percentage of customers charges more than $241 an d$301.60 per month?

Q2) A manufacturing process makes items whose weights are normally distributed. It is known that 22.57% of all the items made weigh between 100 grams up to mean and 49.18% weigh from the mean up to 190 grams

a) Find out the mean.

b) Find out the standard deviation.