1. The average sales of a product 763 pcs. daily standard deviation of 189 pieces. Determine the level of stocks at the date required to meet the demand with a probability of 75%, if the fluctuations of sales are subject to the normal distribution law.
2
. Three-week observation gave the following details about the daily sales (in thousand. Rub.)
I Week 50 65 77 55 67
II Week 80 56 69 72 53
III Week 74 52 58 66 51
Find the average value of daily revenue and the standard deviation of the mean (an unbiased estimate). How likely proceeds will be more than 75 thousand. Rub., If the law is assumed to be normal distribution? (See. Manual section "Point estimates of parameters of distribution").

3. Average revenue per day is 24,600 rubles., The standard deviation of 2300 rubles. Determine the minimum and maximum level of revenue at 95% confidence level, if normal distribution is assumed.

4. You speak on equal footing with two outlets. Your share of the first 50%, and 60% in the second. Weekly income from the first point is a normal random variable with a mean value of 1500 TR and variance t.r.2 10000, and from the second - with the average value 3500 TR and variance 40000 t.r.2 Determine the minimum and maximum amount of your weekly income to a confidence level of 95%.

5. In a week we will have to repay $ 1 million. Rubles. Our weekly income is a normal random variable with a mean value of 800 thousand. Rub. and a standard deviation of 300 thousand. rub. How much we need to take out a loan to pay off the debt with a probability of 90%?