Biased data

The measured data collected in an investigation should be both accurate and precise, as explained below.

• To be accurate, the measured value should be close to the actual or true value.
• To be precise, the measured values should be close to each other when repeated.

To ensure that a sample is random, it should be carefully planned in the context of the question being asked.

You can download the Biased Data: Student Worksheet which further explores accuracy and precision, as well as random sampling.