Question

The mean of 50 observation were calculated as 4.04 when mr.x took by mistake 10 instead of 8 for an observation. the correct mean is

• A. 4.08
• B. 3.95
• C. 4.01
• D. 4

Answer 1

The correct option is D 4

Let the correct mean be $\overline{x}$ and sum S & incorrect be ${\overline{x}}^{\prime }$ & S'

$\Rightarrow {\overline{x}}^{\prime }=\frac{S^{\prime }}{50}=4.04$

$\Rightarrow S^{\prime }=202$

$\Rightarrow S=S^{\prime }-10+8=S^{\prime }-2=200$

$\Rightarrow \overline{x}=\frac{200}{50}=4$

$\Rightarrow \left(D\right)$.