Question

The average rating of 100 observation is 50. If we remove a rating 50 and include rating 150, then what is the new average?
1. 52
2. 51
3. 50.5
4. 52.5

Answer 1

Correct Answer - Option 2 : 51

Given:

Average of 100 observation = 50

Concept used:

Sum of ratings = Average × Number of observation

Calculation:

Sum of ratings = Average × Number of observation

⇒ Required sum = 50 × 100

⇒ Required sum = 5000

If we remove a rating of 50 and include a rating of 150

Overall change = 150 - 50

⇒ Change = 100

New sum = 5000 + 100

⇒ New sum = 5100

New average = New sum/100

⇒ New average = 5100/100

⇒ New average = 51

∴ The new average is 51.