Researchers collected some data to measure the distance betw…

Researchers collected some data to measure the distance between Mars and the Sun.  The distance variable in this study is variable.   Suppose the researchers also collected data on stars using “Stellar classification” – The seven main types are M, K, G, F, A, B and O. This is a classification based on temperature: M stars are the coldest stars and O stars are the hottest. The variable “Stellar classification” would be variable.