The average value of the original data set 12345 is:. x=( 1+2+3+4+5)÷5=3

The variance of the original data set 12345 is S2 =1/5 [(1-3) 2+(2-3) 2+…+(5-3) 2] = 2.

Compare the two sets of data, and add 100 to each digit of the original data to get the new data. According to each number in a set of data, the same number is added, and the variance remains unchanged. The variance of the new data is 2.

The standard deviation is the root symbol of variance. So the standard deviation of the new data is √2.

The answer to the first question is a.

The second question:

The average of the five grades of (1)∫A is: (5+9+8+10+8) ∫ 5 = 8;

The average of five grades of B is: (6+ 10+5+ 10+9) ÷ 5 = 8.

∴ Party A and Party B have the same hit rate;

(2) Variance of five grades of A =1/5x2+(9-8) 2+(8-8) 2+(10-8) 2+(10).

Variance of five grades of B =1/5× [(6-8) 2+(10-8) 2+(5-8) 2+(10-8) 2] =

Since 2.8 < 4.4,

So A's shooting level is more stable.

So, the answer to the second question is E.

The third question:

So the answer to the third question should be a, send a.