A set of data of US covid numbers of cases and deaths each day since Jan 22, 2020 are provided for regression analysis in Excel file 'USA-covid-data.xlsx'. You are asked to use MATLAB commands to curve fit the data for the number of new cases. a. (10 points) Load the data in Excel file 'USA-covid-data.xlsx". Use MATLAB command polyfit to fit the new cases data (column D) with a 4th order polynomial function. You may need to create a vector of days for this question. (You can ignore any Matlab warnings that the polynomial function is badly conditioned) b. (5 points) Use MATLAB command polyval to evaluate the polynomial function obtained from (a) for the days vector you created in (a). c. (10 points) Use MATLAB commands to plot the original data and the curve fitted data on the same figure. There should be two lines on the plot (one original points, and one fit line points). Please include title, axis labels, and legends in the plot. A set of data of US covid numbers of cases and deaths each day since Jan 22, 2020 are provided for regression analysis in Excel file 'USA-covid-data.xlsx'. You are asked to use MATLAB commands to curve fit the data for the number of new cases. a. (10 points) Load the data in Excel file 'USA-covid-data.xlsx". Use MATLAB command polyfit to fit the new cases data (column D) with a 4th order polynomial function. You may need to create a vector of days for this question. (You can ignore any Matlab warnings that the polynomial function is badly conditioned) b. (5 points) Use MATLAB command polyval to evaluate the polynomial function obtained from (a) for the days vector you created in (a). c. (10 points) Use MATLAB commands to plot the original data and the curve fitted data on the same figure. There should be two lines on the plot (one original points, and one fit line points). Please include title, axis labels, and legends in the plot