please show how the process should be done in MATLAB, please show MATLAB CODES

Question 2 (30\%): DNA microarrays are used to study the relative expression of phenotypes under ditferent experimental conditions. One of the commonly studied systems is the yeast. Lets choose four proteins from the NiH dataset and find how their expression proflies are related to the to the expression of a specille mutant phenotype Sigma1276b. a) (10\%6) Calculate the linear regression of the data using P1, P2, P3, and P4 as your predictors and Sigmat 278b as your cutput, do not use the built-in functions Ilike polyitit or linsolve. b) (10\%) Quantily the coelficient of determination (r2) of your model fit created in part (a). c) (10\%) Estimate the value of the expression of Sigma1278b for P1=5,P=3,P3=7 and P4=8