Using data from 100 hospitals, a correlation of r = 0.78 is found between the size of a hospital (measured in number of beds) and the average length of patient stays (measured in days). Which of the following is true?

Group of answer choices

"Severity of illness" is a possible lurking variable that is behind this relationship.

There is a pretty strong positive linear correlation between number of beds and length of hospital stay.

Increasing hospital size must be the cause of longer patient stays.