Question

Unit sales for new product ABC have varied in the first seven months of this year as follows:

Month Jan Feb Mar Apr May Jun Jul
Unit Sales 314 285 158 482 284 310 281
What is the (population) Pearson's coefficient of skewness of the data?
Unit sales for new product ABC have varied in the first seven months of this year as follows:
Month Jan Feb Mar Apr May Jun Jul
Unit Sales 314 285 158 482 284 310 281
What is the (population) standard deviation of the data?

Answer 1

Coefficient of skewness = 0.5785

Population standard deviation = 88.154

Explanation:

Given the data:

Month Jan Feb Mar Apr May Jun Jul

Unit Sales 314 285 158 482 284 310 281

Reordered data : 158, 281, 284, 285, 310, 314, 482

The population mean of the data :

Mean, μ = Σx / n = 2114 / 7 = 302

The median :

1/2(n+1)th term

n = 7

1/2(8)th term

Median = 4th term = 285

The population standard deviation, s :

s = √(Σ(x - μ)²/n)

s = √[(158-302)^2 + (281-302)^2 + (284-302)^2 + (285-302)^2 + (310-302)^2 + (314-302)^2 + (482-302)^2] / 7

s= √(54398 / 7)

s = √7771.1428

s = 88.154

The Pearson Coefficient of skewness :

[3(μ - median)] / s

3(302 - 285) / 88.154

3(17) / 88.154

51 / 88.154

= 0.5785