The unit of correlation coefficient between height in feet and weight in kgs is ____________.

non-existent

The correct answer is Option 4: non-existent

The correlation coefficient is calculated by standardizing the covariance of the two variables, which removes any units. This makes it a pure number without any physical unit. The correlation coefficient ranges from -1 to 1, indicating the strength and direction of the relationship between the two variables, but not the magnitude of their units.

In this case, height in feet and weight in kilograms are not inherently related in a linear way. While there might be some correlation in a specific population, there's no guarantee a taller person will weigh more in kilograms (or vice versa). So, the concept of a unit for the correlation coefficient between these two variables doesn't exist.