Find the standard deviation for the following group of data items.
11, 14, 14.20
The standard deviation is approximately
(Round to two decimal places as needed)
What is it

Suppose a laboratory has a 30 g sample of polonium-210. the half-life of polonium-210 is about 138 days how many half-lives of polonium-210 occur in 1104 days? how much polonium is in the sample 1104 days later? 9; 0.06 g 8; 0.12 g 8; 2,070 g