7. Suppose we run a simple linear regression and find the estimated covariance matrix of the parameter estimators is: [ 12.4 -62.0 | -62.0 312.5 Use this covariance matrix to find the estimated variance of the estimated mean of y when x = 5. What is the estimated variance? (Note that the estimated mean of y when :=5 is Bo + B1.5.)

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7. Suppose we run a simple linear regression and find the estimated covariance matrix of the parameter estimators is: 12.4 -62.0 -62.0 312.5 Use this covariance matrix to find the estimated variance of the estimated mean of y when i = 5. What is the estimated variance? (Note that the estimated mean of y when = = 5 is Bo + 8, - 5.)