Please explain why the conditional function can be treated as a Gauassian RV for part b

[Joint empirical distribution of ECE 313 scores] The scatterplot below shows 205 points, (wi, v;), where u; is the score on exam two, and v; is the score on the final exam, for the it student in ECE313 in a recent semester. The empirical mean and standard deviation for exam two are /x = 67 and ox = 19, the empirical mean and standard deviation for the final exam are my = 152 and oy = 35, and the empirical correlation coefficient (computed using a spreadsheet function) is p =0.71. Visual inspection of the data suggests it is reasonable to assume that the joint distribution of the two scores is jointly normal. Let (X, Y) be jointly normal random variables with the above parameter values. 250 200 150 100 50 20 40 60 100 130 (a) Find E[Y |X = u] as a function of u. (b) Describe in words the conditional distribution of Y given X = u