Statistics - Online Test
Q1. If the two lines of regression are at right angles , then ρ(X,Y) is equal to
Answer : Option C
Explaination / Solution:
Q2. If COV(X,Y) = 0 , then the two lines of the regression are
Answer : Option D
Explaination / Solution:
Using the formulae,
here
therefore
Q3. If the variance of the data is V, then its S.D. is
Answer : Option D
Explaination / Solution:
standard deviation have the same units as the data but variance is mean of the square of differences.
Q4. If the two lines of regression are y = 3x – 5 and y = 2x – 4 , then ρ(X,Y) is equal to
Answer : Option A
Explaination / Solution:
let us assume that y = 3x – 5 and y = 2x – 4 are lines of regression of x on y and y on x respectively,therefore
but sign of is same as and
therefore
Q5. If the median = (mode + 2 mean) μ, then μ is equal to
Answer : Option C
Explaination / Solution:
Q6. If mean = ( 3 median – mode ) x , then the value of x is
Answer : Option A
Explaination / Solution:
We know that, 3median = mode + 2 mean
so, mean= (3 median - mode)/2 ........(1)
comparing equation(1) with the given equation
therefore, x=1/2
Q7. Least square lines of regression give best possible estimates , when ρ(X,Y) is equal to
Answer : Option D
Explaination / Solution:
Least square lines of regression give best possible estimates when the lines coincide at that point ρ=±1
Q8. ρ(X,Y) is equal to
Answer : Option D
Explaination / Solution:
=
Q9. Quartile deviation is nearly equal to
Answer : Option A
Explaination / Solution:
Quartile deviation is approximately 2/3 times the standard deviation.
Q10. For a symmetrical distribution and . The median of the data is
Answer : Option D
Explaination / Solution:
For symmetric distribution,
