Fundamentals of Mathematical Statistics (BCA) 1st Sem Previous Year Solved Question Paper 2022

Practice Mode:
9.

Define Concurrent Deviation method of correlation. Calculate coefficient of concurrent deviation for the following data :

PGREF-625

Explanation

Coefficient of Concurrent Deviation (r) = Σ [(Price - Mean(Price))(Demand - Mean(Demand))] / √[Σ(Price - Mean(Price))² * Σ(Demand - Mean(Demand))²]

First, calculate the means (average) for both Price and Demand:

Mean(Price) = (25 + 28 + 30 + 23 + 35 + 38 + 39 + 42) / 8 = 31.75

Mean(Demand) = (35 + 34 + 35 + 30 + 29 + 38 + 26 + 23) / 8 = 30.125


Σ [(Price - Mean(Price))(Demand - Mean(Demand))] = -33.09375 - 14.53125 - 8.53125 + 1.09375 - 3.65625 + 49.21875 - 29.90625 - 73.15625 = -109.965

Σ(Price - Mean(Price))² = (6.75)² + (3.75)² + (1.75)² + (8.75)² + (3.25)² + (6.25)² + (7.25)² + (10.25)² = 446.0625

Σ(Demand - Mean(Demand))² = (4.875)² + (3.875)² + (4.875)² + (0.125)² + (1.125)² + (7.875)² + (4.125)² + (7.125)² = 244.890625

Now, calculate the coefficient of concurrent deviation:

r = -109.965 / √(446.0625 * 244.890625) ≈ -109.965 / 283.3769148 ≈ -0.3883

So, the coefficient of concurrent deviation (r) is approximately -0.3883. This value indicates a moderate negative correlation between Price and Demand.