5. The formula for the ordinary least squares slope parameter in a simple linear regression model is as follows:
Suppose the simple linear regression model is given as y = β0 + β1x + ε. Assuming Σ(xi - x̄)² > 0, which of the following best represents the i=1 ordinary least squares (OLS) slope parameter?
Where:
Pxy = the sample covariance between x and yi.
Sx = the sample standard deviation of x.
Sy = the sample standard deviation of yi.
6. Suppose you collect data and fit a simple linear regression model. The slope parameter, β1, must be greater than 0.