Question

Please HELP ME !!!!!

Answer 1

Answer: C

Explanation:

Mean is 10(.27)+20(.28)+30(.45) = 21.8

So standard deviation
`=\sqrt{(10-21.8)^(2) \cdot 0.27+(20-21.8)^(2) \cdot 0.28+(30-21.8)^(2) \cdot 0.45} \approx 8.29`