Regression covariance

Question

2. Suppose that we are interested in the relationship between the age of the individuals who are members of our managed-care organization and the use of physician care, as measured by visits. Suppose also that after selecting 15 members at random we obtained the following paired observations: Visits: 3 5 4 2 1 3 6 7 4 5 10 1 2 3 8 Age 28 45 50 19 16 27 54 63 32 42 68 19 23 30 61 Use these data to find the covariance between age and the number of visits.

Answer 1

I think you are looking for a covariance formula

$$\text{Cov}(x,y) = \frac{1}{N}\sum_{i = 1}^N(x_i-\bar x)(y_i-\bar y)$$ where $x,y$ are lists of data and $\bar x, \bar y$ are the means.