Tom hypothesizes that there is a relationship between air pressure and rainfall. He records air pressure and rain amounts for three months. Each month, he seems to get different results. What is the most likely explanation for this?

Missing data points

Step-by-step explanation:

Given that there are 12 calendar months in a year, and there are clearly defined raining season in some areas which may last for months, following periods of low rainfall or zero precipitation, the sample should include all the months of the year so as to ensure, that the effect that causes rainy season such as the landward direction of moist air from the sea or the seaward of air during periods of dry season.

Other possible causes includes;

Heteroscedasicity

This occurs when the variability of the dependent variable is not constant with regards to the independent variable

Multiple linear regression

The relationship between rainfall and air pressure as well as other factors is a multiple linear regression