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The Big Mac Index dataset contains information on the price of Big Macs and currency exchange rates for the

US dollar worldwide at times since $2000.$ Mean absolute error results for data from China are shown in the

table. $MA{E}^{**}$ was calculated with one more instance than MAE.

Using the linear regression model before the additional instance is added, the predicted currency

exchange rate differs, on average, by

from the observed currency exchange rate for the

associated Big Mac price.

Comparing the MAE values for the models before the additional instance is added, the

regression model performs better.

When the new data point is added, the MAE changes more for the

$|$ regression model.