Question

Discuss the appropriate statistical technique that can explain the variation in the daily sales because of the daily inventory holding cost Post-COVID-19 post COVID 19. Justify your answer.                                                           

Answer 1

Since I answered previous question, I think the data is same because you have not provided.

Pre-covid 19

Linear relationship is not good but sales increase with increase in cost

This means that for 1 unit increase in x there is 0.3014 units increase in y.

better

This means that for one unit increase in x there is (-2.5213+37.457=34.9357) 34.9357 units increase in y.

even better as R-sq increases

Best with 99.78% variability in Sales explained by Inventory Cost (X)

Now,

Post Covid =19 for same plot:

This means that for 1 unit increase in x there is 1.1523 units decrease in y

Linear is also meaningful here as it explains 77.45% variability but here, sales decrease with increase in cost

So, model/relationship has indeed changed

Please rate my answer and comment for doubt.