Tamilnadu State Board New Syllabus Samcheer Kalvi 11th Business Maths Guide Pdf Chapter 9 Correlation and Regression Analysis Ex 9.1 Text Book Back Questions and Answers, Notes.

## Tamilnadu Samacheer Kalvi 11th Business Maths Solutions Chapter 9 Correlation and Regression Analysis Ex 9.1

### Samacheer Kalvi 11th Business Maths Correlation and Regression Analysis Ex 9.1 Text Book Back Questions and Answers

Question 1.

Calculate the correlation co-efficient for the following data:

Solution:

Coefficient of correlation

Question 2.

Find the coefficient of correlation for the following:

Solution:

Question 3.

Calculate the coefficient of correlation for the ages of husbands and their respective wives:

Solution:

Without deviation:

N = 10

Coefficient of correlation

= \(\frac{1783}{45 \times 39.76}\)

= 0.9965

Note: We can do the above problem using deviations taken from arithmetic means of X and Y. i.e., using

r = \(\frac{\Sigma \mathrm{XY}}{\sqrt{\Sigma \mathrm{X}^{2} \Sigma \mathrm{Y}^{2}}}\)

Question 4.

Calculate the coefficient of correlation between X and Y series from the following data:

The summation of product deviations of X and Y series from their respective arithmetic means is 122.

Solution:

N = 15, \(\overline{\mathrm{X}}\) = 25, \(\overline{\mathrm{Y}}\) = 18, x = X – \(\overline{\mathrm{X}}\), y = Y – \(\overline{\mathrm{Y}}\), Σx^{2} = 136, Σy^{2} = 138, Σxy = 122

Correlation coefficient

Question 5.

Calculate the correlation coefficient for the following data:

Solution:

N = 10, ΣX = 310, ΣY = 340, Σx^{2} = 870, Σy^{2} = 720, Σxy = 178

Correlation coefficient

Question 6.

Find the coefficient of correlation for the following:

Solution:

N = 8, ΣX = 600, ΣY = 724, Σdx^{2} = 1172, Σdy^{2} = 3372, Σdxdy = -146

Correlation coefficient

Question 7.

An examination of 11 applicants for an accountant post was taken by a finance company. The marks obtained by the applicants in the reasoning and aptitude tests are given below.

Calculate Spearman’s rank correlation coefficient from the data given above.

Solution:

N = 11, Σd^{2} = 22

Rank correlation

Question 8.

The following are the ranks obtained by 10 students in commerce and accountancy are given below:

To what extent is the knowledge of students in the two subjects related?

Solution:

N = 11, Σd^{2} = 128

Rank correlation

Question 9.

A random sample of recent repair jobs was selected and the estimated cost and actual cost were recorded.

Calculate the value of spearman’s correlation coefficient.

Solution:

N = 8, Σd^{2} = 8

Rank correlation

Question 10.

The rank of 10 students of the same batch in two subjects A and B are given below. Calculate the rank correlation coefficient.

Solution:

N = 10, Σd^{2} = 226

Rank correlation