Question

If the scores of 3 students in a test are 5,6 and 7. Find the standard deviation of their scores.

Answer 1

0.82

Explanation:

Step 1: (Calculating mean)

=>
`(5+6+7)/(3)`

=>
`(18)/(3)`

=> Mean = 6

Step 2:

=> (5-6)² = (-1)² = 1

=> (6-6)² = (0)² = 0

=> (7-6)² = (1)² = 1

Step 3: (Adding all values calculated in step 2)

=> 1+ 0 + 1 = 2

Step 4: (Dividing the result in step 3 by no. of observations)

=> 2/3 = 0.67

Step 5: (Get square root to calculate the deviation.)

=>
`√(0.67)` = 0.82