Question

It was projected that a store would sell 1,200 TVs over Thanksgiving weekend, but the store sold only 845 TVs. What percent of error was made on the projection?

Answer 1

The percentage error is calculated using the formula shown below;

`\begin{gathered} Per\text{ error=}(|Approx-exact|)/(exact)*100 \\ Approximate\text{ value is the value achieved/observed in the experiment} \\ \text{Exact value is the value targeted at the beginning of the experiment.} \\ \text{Percent error=}(|845-1200|)/(1200)*100 \\ \text{Percent error=}(355)/(1200)*100 \\ \text{Percent error=29.583333}\ldots \\ \text{Rounded up to the nearest whole number, the percentage error is;} \\ \text{Percent error}\approx30 \end{gathered}`

The percentage error is 29.583333...

This can be rounded up to the nearest whole number as 30%

Please note that in the formula applied, the approximate value minus the exact value (the numerator) is expressed as an absolute value, which means it must always be a positive value. Hence, 845 minus 1200 which equals negative 355 is expressed as a positive number.