solutions of statistics for economics by T.R.Jain

V.K.ohri

how can we derive the formula of karl pearson's cefficient of correlation in shortcut method?

prove that coefficient of correlation always lies between -1 to +1

From the following data relating to playing habits in various age groups of 900 students. Calculate coefficient of correlation between age group and playing habits.

Age group = 15-16, 16-17, 17-18, 18-19, 19-20, 20-21

No.of students = 250, 200, 150, 120, 100, 80

Regular Players = 200, 150, 90, 48, 30, 12

plse solv Q. 13 , Q 14 , Q 15 of saraswati statistics book on pg 190

From the following data determine Karl Pearson's coefficient of correlation between X and Y series for 15 pairs.

X SERIES :

Mean = 80

Sum of squares of deviation from A.M. = 56

Sum of product of deviations of X and Y from their respective Means = 92

Y SERIES :

Mean = 120

Sum of squares of deviation from A.M. = 156

Sum of product of deviations of X and Y from their respective Means = 92

how to calculate the step deviation

find out rank difference correlation of x and y

x- 80,78,75,75,58;67;60;59

y-12,13,14,14,14,16,15,17

can we use assumed mean method to calculate karl pearson's correlation coefficient

Calculate the correlation coefficient between X and Y and comment on their relationship

Following data relates to density of population, number of deaths and population of various cities. Calculate death rate and Karl pearson coefficient between density of population and death rate.

Cities = P, Q, R, S, T, U

Density of population = 200, 500, 700, 500, 600, 900

No. of deaths = 840, 300, 312, 560, 1440, 1224

Population = 42000, 30000, 24000, 40000, 90000, 72000

what is assumed mean method for karl pearson's coefficient?

by using karl pearson actual mean method

Age (year); 1 2 3 4 5

weight(kg);3 4 6 7 10

b. Calculate coefficient of correlation from the following data.X- 1, 2, 3, 4, 5, 6 ,7, 8, 9

Y- 9, 8 ,10, 12 ,11 ,13, 14, 16, 15

Calculate the correlation coefficient between the heights of fathers in inches (X) and their sons (Y)

X

65

66

57

67

68

69

70

72

Y

67

56

65

68

72

72

69

71

Why is r preferred to covariance as a measure of association?

q. calculate corelation coefficient

x ; 65 66 57 67 68 69 70 72

y ; 67 56 65 68 72 72 69 71

from dis formula ;

r= ∑xy ∕ Nsd(x) sd(y)

how to draw a scatter diagram when r= -0.9 and r= o.3

If r_xy = 0 the variable X and Y are

(i) linearly related

(ii) not linearly related

(iii) independent

Please make me understand about karl pearsons cofficient of correlation..

I have to learn how to construct correlation from all methods...???

Why does rank correlation coefficient differ from Pearsonian correlation coefficient?

From the following information determine coefficient of correlation between X and Y series.

X SERIES :

No. of items = 15

Mean = 25

S.D. = 3.01

Sum of squares of deviation from Mean = 136

Sum of product of deviations of X and Y from their respective means = 122

Y SERIES :

No. of items = 15

Mean = 18

S.D. = 3.03

Sum of squares of deviation from mean = 138

Sum of product of deviations of X and Y from their respective means = 122

In the method of karl pearson for the coefficient of correlation can we find the standard deviation by the root of variance if discrete sries is given to us and then proceed further ?

Calculate the correlation coefficient between X and Y and comment on their relationship:

calculate the correlation cofficient between X and Y and comment on their relationship:

X -3 -2 -1 1 2 3

Y 9 4 1 1 4 9

following data relates to age group and percentage of regular players . calculate karl pearson 's cofficient of correlation. age group : 20-25 25-30 30-35 35-40 40-45 45-50 % of regular players : 40 35 28 20 15 5

The unit of correlation coefficient between height in feet and weight in kgs is

(i) kg/feet

(ii) percentage

(iii) non-existent

Differentiate between Karl pearson's coefficient of correlation and spearman's rank correlation.

calculate coefficient of correlation of the age of husband and wife using karl pearson's method

Can simple correlation coefficient measure any type of relationship?

According to the spearman's rank correlation in ncert book (page101) what does the line - "It is the product moment correlation between the ranks" mean

Define Scattered Diagram??

actual mean method of karl pearson

When is rank correlation more precise than simple correlation coefficient?

Does zero correlation mean independence?

Q.1. Plot the following data asa a scatter diadram and comment over the result :

X : 1110 15 13 10 16 13 8 17 14

Y : 67 99 7 11 9 6 1211

Q.2. From the following data compute the product moment corralation between x and y .

x series y series

Arithmetic mean 25 18

square of deviations from arithmetic mean136 138

Q.3. Calculate karl pearsons cofficient of corralation on the following data :

x : 1518 21 24 27 3036 39 42 48

y : 25 25 27 27 3133 35 41 4145

Q.4. Calculate correlation cofficient between x, the number of raniy days per month and y , the number of rain coats sold in that month in a certain shop for 12 month . interpret the results .

X : 14 8 18 10 22 9 3 5 6 11 13 13

Y : 15 11 20 12 15 7 3 4 7 10 11 29

Q.5. The deviations from their means of two series (x and y) are given below :

x : -4 -3 -2 -1 0 +1 +2 +3 +4

y : +3 -3 -4 0 +4 +1 +2 -2 -1

Q.6. Find suitable coefficient of correlation for the following data :

Fertilizers used (in tons) : 15 18 20 24 30 35 40 50

Productivity (in tons) : 85 93 95 105 120 130150 160

what is partial correlation?

Name the methods used to measure correlation and also define them briefly.

what are the general guidelines for construction of frequency distribution

Model Test Paper 4 Q31: answer for standard deviation sum is -0.895 and not as given.