NCERT Solutions for Class 11 Economics Statistics for Economics Chapter 7

Correlation Class 11

Exercise : Solutions of Questions on Page Number : 104

Q1 :

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

(i) kg/feet

(ii) percentage

(iii) non-existent

As there is non-existent of correlation between the height in feet and weight in kilograms, so the unit of correlation between the two is zero.

Q2 :

The range of simple correlation coefficient is

(i) 0 to infinity

(ii) minus one to plus one

(iii) minus infinity to infinity

The range of simple correlation coefficient is from (-) 1 to (+) 1

Q3 :

If rxy is positive the relation between X and Y is of the type

(i) When Y increases X increases

(ii) When Y decreases X increases

(iii) When Y increases X does not change

Q4 :

If rxy = 0 the variable X and Y are

(i) linearly related

(ii) not linearly related

(iii) independent

Q5 :

Of the following three measures which can measure any type of relationship

(i) Karl Pearson's coefficient of correlation

(ii) Spearman's rank correlation

(iii) Scatter diagram

Q6 :

If precisely measured data are available the simple correlation coefficient is

(i) more accurate than rank correlation coefficient

(ii) less accurate than rank correlation coefficient

(iii) as accurate as the rank correlation coefficient

Q7 :

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

Q8 :

Can r lie outside the -1 and 1 range depending on the type of data?

Q9 :

Does correlation imply causation?

Q10 :

When is rank correlation more precise than simple correlation coefficient?

Q11 :

Does zero correlation mean independence?

Q12 :

Can simple correlation coefficient measure any type of relationship?

Q13 :

Collect the price of five vegetables from your local market every day for a week. Calculate their correlation coefficients. Interpret the result.

Q14 :

Measure the height of your classmates. Ask them the height of their benchmate. Calculate the correlation coefficient of these two variables. Interpret the result.

Q15 :

List some variables where accurate measurement is difficult.

Q16 :

Interpret the values of r as 1, -1 and 0.

Q17 :

Why does rank correlation coefficient differ from Pearsonian correlation coefficient?

Q18 :

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

 X 65 66

Q19 :

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

 X -3 -2

Q20 :

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

 X 1 3 4