Pathfinder NDA / NA National Defence Academy and Naval Academy Entrance Examination Mathematics>Chapter 31 - Statistics>Practice Exercise>Q 4

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IMPORTANT

Earn 100

Consider the following frequency distribution:

Class interval $0 - 10$ $10 - 20$ $20 - 30$ $30 - 40$ $40 - 50$

Frequency $14$ $f_{2}$ $28$ $f_{4}$ $15$

If the sum of the frequencies is $100$ and median is $25$ , then $f_{2}$ and $f_{4}$ will be

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Important Questions on Statistics

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IMPORTANT

Pathfinder NDA / NA National Defence Academy and Naval Academy Entrance Examination Mathematics>Chapter 31 - Statistics>Practice Exercise>Q 5

If the standard deviation of

15

items is

6

and each item is decreased by

1

, then standard deviation will be

MEDIUM

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IMPORTANT

Pathfinder NDA / NA National Defence Academy and Naval Academy Entrance Examination Mathematics>Chapter 31 - Statistics>Practice Exercise>Q 6

The standard deviation in a variable

x

is

σ

. The standard deviation of the variable

\frac{a x + b}{c}

; where

a, b

and

c

are constants, is

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IMPORTANT

Pathfinder NDA / NA National Defence Academy and Naval Academy Entrance Examination Mathematics>Chapter 31 - Statistics>Practice Exercise>Q 7

If

\bar{x} = \bar{y} = 0, Σ x_{i} y_{i} = 12, σ_{x} = 2, σ_{y} = 3

and

n = 10

then the coefficient of correlation is

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IMPORTANT

Pathfinder NDA / NA National Defence Academy and Naval Academy Entrance Examination Mathematics>Chapter 31 - Statistics>Practice Exercise>Q 8

If

b_{y x}

and

b_{x y}

are regression coefficients of

y

on

x

and

x

on

y

respectively, then which of the following statements is true?

EASY

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IMPORTANT

Pathfinder NDA / NA National Defence Academy and Naval Academy Entrance Examination Mathematics>Chapter 31 - Statistics>Practice Exercise>Q 9

If

n = 10, Σ x = 4, Σ y = 3, Σ x^{2} = 8, Σ y^{2} = 9

and

Σ x y = 3

, then coefficient of correlation is

EASY

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IMPORTANT

Pathfinder NDA / NA National Defence Academy and Naval Academy Entrance Examination Mathematics>Chapter 31 - Statistics>Practice Exercise>Q 10

The standard deviation of some consecutive integers is found to be

2

. Which of the following statements best describes the nature of the consecutive integers?

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IMPORTANT

Pathfinder NDA / NA National Defence Academy and Naval Academy Entrance Examination Mathematics>Chapter 31 - Statistics>Practice Exercise>Q 11

The two lines of regression are

8 x - 10 y = 66

and

40 x - 18 y = 214

and variance of

x

series is

9

. What is the standard deviation of

y

series?

EASY

NDA & NA EE

IMPORTANT

Pathfinder NDA / NA National Defence Academy and Naval Academy Entrance Examination Mathematics>Chapter 31 - Statistics>Practice Exercise>Q 12

What is the standard deviation of numbers

7, 9, 11, 13

and

15

?