Class interval	\ \					\ \	\ \
\ 2 - 8 \	\ 5 \	\   \ 5 \	\ 5 \	25	125	-21.8	21.8
12 - 16	\ 15 \	\ 8 \	\ 13 \	120	1800	-11.8	11.8
\ 22 - 28 \	25	\ 15 \	\ 28 \	375	9375	-1.8	1.8
\ 32 - 38 \	35	\ 16 \	\ 44 \	560	19600	8.2	8.2
\ 42 - 48 \	\ 45 \	\ 6 \	\ 50 \	270	12150	18.2	18.2
\   \	\   \	\ 50 \	\   \	1350	43050		61.8

= 61.8/50

= 1.236

Mean

Variance

Standard deviation

.