In: Statistics and Probability
According to an NRF survey conducted by BIGresearch, the average family spends about $237 on electronics (computers, cell phones, etc.) in back-to-college spending per student. Suppose back-to-college family spending on electronics is normally distributed with a standard deviation of $54. If a family of a returning college student is randomly selected, what is the probability that:
(a) They spend less than $140 on back-to-college
electronics?
(b) They spend more than $370 on back-to-college electronics?
(c) They spend between $140 and $180 on back-to-college
electronics?
For letter A, I got as far as -1.796 after diving by 54. When I look at the Z chart I look at 1.80 which is (.4641)
But looking at other examples similar to this problem with just the X variable being different, when I work out that example problem I'm reference I don't get the same answer for they come to. I only get to the -1.796. Not sure what step I'm missing to do after that.