Answer:
F(4) = -3
Step-by-step explanation:
First, you would plug in 4 for x. PEMDAS, so you would multiply -3 and 4, giving you -12. Then add 9, which gives you -3.
A suitable probability calculator will tell you that probabilty is about 25.9%.
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The normalcdf function on this calculator gives an area between a lower and upper limit. If the upper limit is more than about 8 standard deviations above the mean, the 10th decimal place is unaffected. Since the standard deviation here is about 5, we need to have an upper limit that is about 40 above the mean of about 30. We have chosen 80 as a nice round number and to give a little more margin.
If you're asking the difference between 14 ft and 21 ft your answer is 7 ft, just subtract 14 from 21