Hi! Could someone help me with a practice question on standard deviation please?
“Returns from a project are normally distributed with a mean of 220k and a standard deviation of 160k. What is the probability of the project losing more than 80k? Give your answer to the nearest whole %”
I began by subtracting 220k from 80k, then divided the answer (140k) by the standard deviation (160k) to get a Z score of 0.875. The table shows this as 0.3106. I then subtracted this from 0.5 to find out the probability of losing more than 80k, which gives 18.9%, rounded to 19%.
The answer is not 19%. I can’t find the answer to this question. It’s on a practice exam that doesn’t give answers – it only says if you are correct. Where am I going wrong?
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