Question

Given below are the marks out of 25 of 5 students in mathematics test. Calculate the Varience

and standard deviation of these observations. Marks : 10, 13, 17, 20, 23.​

Answer 1

Answer:

Solution :

Here, Mean (X¯¯¯)=8+12+13+15+225=705=14

∴xi−X¯¯¯=−6,−2,−1,1,8

⇒(xi−X¯¯¯)2=36,4,1,1,64

∴∑(xi−X¯¯¯)2=106

Now, Variance (σ2)=1n∑(xi−X¯¯¯)2=1065=21.2

Standard deviation (σ)=21.2−−−−√=4.6