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Distance travelled in a week by sales staff employed by nationwide security firm is approximately normally distributed with a mean of 200 miles and standard deviation of 48 miles. Estimate the percentage of staff who in a week travel:
1.
a)less than 80 miles
b)more than 250 miles
c)between 100 and 300 miles
2.A reduced mileage rate is to be introduced which is to be set such that approximately 20% of the sales staff will be affected? What is the maximum miles per week that a member of staff could travel before reaching the reduced mileage rate?
3)
Complete this sentence:
"80% of sales staff travel between ____ and ______ miles each week".

  • statistics -

    I need help for this question asap thanx

  • statistics -

    1. z = (x - mean)/SD

    Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions related to the Z scores.

    Reverse the process for the last two questions.

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