Let X take 4 values x1 1; x2 3; x3 5; x4 3. (a) Calculate the arithmetic average x 4

Let X take 4 values x1 ¼ 1; x2 ¼ 3; x3 ¼ 5; x4 ¼ 3.

(a) Calculate the arithmetic average x ¼
4 i¼1xi

.

4

(b) Calculate
4 i¼1ð Þ xi  x

(c) Calculate
4 i¼1ð Þ xi  x 2

(d) Calculate
4 i¼1x2 i

 4x2