A simple random sample consists of three observations 7, 9, 11. The point estimate of the population standard deviation is :
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 2
$s=\sqrt{\frac{∑(x_i-\bar x)^2}{n-1}}$
Mean, $\bar x=\frac{7+9+11}{3}=9$
$s=\sqrt{\frac{4+0+4}{3-1}}=\sqrt{\frac{8}{2}}=2$