A seasonal index for a monthly series is about to be calculated on the basis of three years' accumulation of data. The three previous July values were 110, 150, and 130. The average over all the 36 months from the three years is 190. The approximate seasonal index for July is:2.0530.3840.6840.287

Option C) 0.684      

Step-by-step explanation:

We are given the following in the question:

Three previous July values:

110, 150, 130

Average July value =

Average over three years = 190

We have to find the seasonal index of July.

Formula:

Thus, the correct answer is

Option C) 0.684

y=-2.5x+12.5

step-by-step explanation:

5y=2x+10

y=0.4x+2

slope=-2.5

5=-2.5*3+b

b=12.5