5. Daily sales of a store is normally distributed with mean u=180 Rials and variance o2 =100. Find the probability that total sales over a period of nine days is more than 1800 Rials. Z= p=

Times for a procedure are normally distributed. There are 2 methods. Method A has a mean of 25 minutes and  a standard deviation of 8 minutes. Method B has a mean of 29 minutes and a standard deviation of 4 minutes. Which procedure is preferred if it must be completed within 33 minutes?

Suppose X ~ N(6, 2). What value of x is two standard deviations to the right of the mean?

= 222 mg/dLi and Total cholesterol levels for middle aged men (aged 55 – 64) follow approximately a normal distribution with mean, µ standard deviation, o = 37 mg/dLi. Those with a total cholesterol of 240 mg/dLi or higher have "high" cholesterol (and have twice the risk of coronary heart disease as someone with a total cholesterol less than 200 mg/dLi) Find the Z-score (standard score) for an observation of 290 mg/dl.