Please explain it detail to properly understand this concept.

3. Suppose we are given a data points (93,, 9,], 1 g 1? 5 n and we want to do a linear least squares polynomial t to given data. (a) Using the standard basis functions, {1, at}, derive the equations for the least squares linear approximation. (b) Suppose the given data is such that n = 21, 21-;11; : 63, 2;, 9:? = 219.8, 2:13;,- = 9.3, and E?=1$y = 60.7. Using your work in part (a) nd the lin- ear least squares approximation to the data