The actual sales and sales forecasts for a product for the past 5 weeks are as follows.

Week	Actual Sales (number of units)	Sales Forecast (number of units)
Five weeks ago	47	47
Four weeks ago	51	49
Three weeks ago	48	47
Two weeks ago	50	49
Last week	46	45

Calculate the Mean Squared Error (MSE) measure for these 5 weeks.

Group of answer choices

3.4 unit ²

1.16667 unit ²

2.5 unit ²

1.6 unit ²

1.4 unit ²