Planck's law In 1880, André-Prosper-Paul Crova published a diagram of the three-dimensional appearance of the graph of the strength of thermal radiation as a function of wavelength and temperature. He determined the spectral variable by use of prisms. He analyzed the surface through what he called "isothermal" curves, sections for a single temperature, with a spectral variable on the abscissa and a power variable on the ordinate. He put smooth curves through his experimental data points. They had one peak at a spectral value characteristic for the temperature, and fell either side of it towards the horizontal axis. Such spectral sections are
Paired data medicine. In this case the data is "paired" as it is likely the blood pressure "after" giving the medicine will be related to the blood pressure of that patient "before" the medicine was given. The statistical tests used to compare sets of data have been designed for data that is either paired or unpaired and it is important to use the correct test to prevent erroneous results. Examples of tests for unpaired data: Examples of tests suitable for paired data: Paired data Scientific experiments often consist of comparing two or more sets of data. This data is described as unpaired