If the mean of the data: 7, 8, 9, 7, 8, 7, λ , 8 is 8, then the variance of this data is :

Question

If the mean of the data: 7, 8, 9, 7, 8, 7, λ , 8 is 8, then the variance of this data is : (A) (7/8) (B) 1 (C) (9/8) (D) 2

Tardigrade Admin · Accepted Answer

Given :- Mean ( barx)=8=(7+8+9+7+8+7+λ+8/8) ⇒ 64=54+λ ⇒ λ=10 Therefore variance (σ2)= ( Sigma(xi- barx)2/8) =(1/8)((7-8)2+(8-8)2+(9-8)2+(9-8)2+(7-8)2+(8-8)2+(7-8)2+(10-8)2+(8-8)2. =(1/8)(8)=1

Q. If the mean of the data : $7, 8, 9, 7, 8, 7, λ, 8$ is $8$ , then the variance of this data is :

$\frac{7}{8}$

1

$\frac{9}{8}$

2

Q. If the mean of the data : 7,8,9,7,8,7,λ,8 is 8, then the variance of this data is :

87​

1

89​

2

Given :- Mean (xˉ)=8=87+8+9+7+8+7+λ+8​ ⇒64=54+λ ⇒λ=10 Therefore variance (σ2)=8Σ(xi​−xˉ)2​ =81​((7−8)2+(8−8)2+(9−8)2+(9−8)2+(7−8)2+(8−8)2+(7−8)2+(10−8)2+(8−8)2 =81​(8)=1

Q. If the mean of the data : $7, 8, 9, 7, 8, 7, λ, 8$ is $8$ , then the variance of this data is :

$\frac{7}{8}$

$\frac{9}{8}$