The mean of 40 observations is 20 and their standard deviation is 5. If the sum of the squares of the observations is k , then the value of (k/1000) is

Question

The mean of 40 observations is 20 and their standard deviation is 5. If the sum of the squares of the observations is k , then the value of (k/1000) is (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

n=40 barx=20 σ =05 (σ )2=( displaystyle ∑ xi2/40)-( barx)2 25=( displaystyle ∑ xi2/40)-400⇒ displaystyle ∑ xi2=17000

Q. The mean of $40$ observations is $20$ and their standard deviation is $5.$ If the sum of the squares of the observations is $k$ , then the value of $\frac{k}{1000}$ is

$n = 40$
$\overset{x}{ˉ} = 20$
$σ = 05$
$(σ)^{2} = \frac{\sum x _{i}^{2}}{40} - (\overset{x}{ˉ})^{2}$
$25 = \frac{\sum x _{i}^{2}}{40} - 400 \Rightarrow \sum x_{i}^{2} = 17000$

Q. The mean of 40 observations is 20 and their standard deviation is 5. If the sum of the squares of the observations is k , then the value of 1000k​ is

n=40 xˉ=20 σ=05 (σ)2=40∑xi2​​−(xˉ)2 25=40∑xi2​​−400⇒∑xi2​=17000

Q. The mean of $40$ observations is $20$ and their standard deviation is $5.$ If the sum of the squares of the observations is $k$ , then the value of $\frac{k}{1000}$ is

$n = 40$
$\overset{x}{ˉ} = 20$
$σ = 05$
$(σ)^{2} = \frac{\sum x _{i}^{2}}{40} - (\overset{x}{ˉ})^{2}$
$25 = \frac{\sum x _{i}^{2}}{40} - 400 \Rightarrow \sum x_{i}^{2} = 17000$