complete matlab task urgent

pls find attached task Technical tasks: 1. numerically determine whether the selected estimators are unbiased 2. numerically evaluate the estimation error variance of the selected estimators as a function of signal-to-noise ratio 3. given some value of signal-to-noise ratio, plot the (average) estimation error variance versus the number of observed samples number 3 from technical tasks says plot the average estim... asking for a plot demonstration based on the problems chosen. Only question 1 and 4 needed .