Question

Fill In the Blanks

If the mean of 12 observations is 15. If two observations 20 and 25 are removed, then the mean of remaining observations is _________.

Answer 1

We know

Mean = $\frac{\mathrm{Sum}\mathrm{of}\mathrm{observations}}{\mathrm{Number}\mathrm{of}\mathrm{observations}}$

⇒ Sum of observations = Mean × Number of observations

Mean of 12 observations = 15 (Given)

∴ Sum of 12 observations = 15 × 12 = 180

If two observations 20 and 25 are removed, then

Sum of remaining 10 observations = Sum of 12 observations − 20 − 25

⇒ Sum of remaining 10 observations = 180 − 20 − 25 = 135

∴ Mean of remaining 10 observations = $\frac{\mathrm{Sum}\mathrm{of}\mathrm{remaining}10\mathrm{observation}}{10}=\frac{135}{10}=13.5$

Thus, the mean of remaining observations is 13.5.

If the mean of 12 observations is 15. If two observations 20 and 25 are removed, then the mean of remaining observations is ___13.5___.