1
NDA 2018 Paper 1
MCQ (Single Correct Answer)
+2.5
-0.83
Let $$\overline x $$ be the mean of x1, x2, x3, ....., xn. If xi = a + cyi for some constants a and c, then what will be the mean of y1, y2, y3, ....., yn ?
A
a + c$$\overline x $$
B
a $$-$$ $${1 \over c}\overline x $$
C
$${1 \over c}\overline x $$ $$-$$ a
D
$${{\overline x - a} \over c}$$
2
NDA 2018 Paper 1
MCQ (Single Correct Answer)
+2.5
-0.83
Consider the following statements

I. If the correlation coefficient rxy = 0, then the two lines of regression are parallel to each other.

II. If the correlation coefficient rxy = 1, then the two lines of regression are perpendicular to each other.

Which of the above statements is/are correct?
A
Only I
B
Only II
C
Both I and II
D
Neither I nor II
3
NDA 2018 Paper 1
MCQ (Single Correct Answer)
+2.5
-0.83
If 4x $$-$$ 5y + 33 = 0 and 20x $$-$$ 9y = 107 are two lines of regression, then what are the values of $$\overline x $$ and $$\overline y $$ respectively ?
A
12 and 18
B
18 and 12
C
13 and 17
D
17 and 13
4
NDA 2018 Paper 1
MCQ (Single Correct Answer)
+2.5
-0.83
Consider the following statements

I. Mean is independent of change in scale and change in origin.

II. Variance is independent of change in scale but not in origin.

Which of the above statements is/are correct?
A
Only I
B
Only II
C
Both I and II
D
Neither I nor II
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