1 Types of data sets

Scientists collect many different types of information, but sets of data may be very loosely classified into two different types. In the first type, so-called ‘repeated measurement’, an individual quantity is measured a number of times. An astronomer wanting to determine the light output of a star would take many measurements on a number of different nights to even out the effects of the various possible fluctuations in the atmosphere that are a cause of stars ‘twinkling’. In the second type of investigation, so-called ‘sampling’, a proportion of the members of a large group are measured or counted. A botanist interested in the average size of Primrose plants in a wood would try to choose representative samples of plants from different parts of the wood and measure those.

You will look at how to handle both types of data sets in the next two weeks, starting with repeated measurements.