Answer:
18
Step-by-step explanation:
162 / 2 = 81
the answer is D
The formula to calculate standard deviation from probability is \sqrt(n*p*(1-p)). n is the sample size, and 200 in this case (number of putts for practice). p is 80% or 0.8, the probability that he can make it. So the standard deviation is \sqrt(200*0.8*(1-0.8)=\sqrt(200*0.8*0.2)=\sqrt(16)=4.
It was about 17.4%
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% error=
actual value-estimated value
Then divide that by actual value
