I would like to understand how can I find the sample variance of residual in steps if I have all these information

Consider dataset X = (80, 81, 79,82,83, TB, 75) and Y = (108,107,10.6,11.7,10,10.9,9.5). and the linear regression model Y = a + bX + e, where e is the residual term. 1. Calculate the least squares estimator of the slope. 2. Calculate the least squares estimator of the intercept. 3. Interpret these parameters. Solution: 2 49,? = 44624 X = 79.71429 SS...c = Z x? 71002 2 43.42957 2 2,-3.7,- = 5920.2 1? = 10.6 55,, = 2 2,4,7,- 74221? = 5920.2 7 - 79.71429 - 10.6 = 6.399662 We will have 53 6: SS\"? = 5.399682/43.42857 = 0.1243348 This means as X increases by one unit, the response Y will increase by 0.1243343. and 6 = g 73.7.- = 0.6367397 This means as X = 0. the response Y is 0.6887397