How do I make my graph print with a line of fit (red solid line) going up, and also 95% confidence bands.

%These commands clear the workspace and command window, in that order.
clear
clc

%Makes long numbers
format long g

%Density Values
d=[4879 12104 12756 6792 142984 120536 51118 49528]'; 
%Gravity Values
g=[3.7 8.9 9.8 3.7 23.1 9.0 8.7 11.0]';

%Meters converstion
D= d.*1000;

%Gravitational Constant
G=6.674e-11;

p=3.*g./(2*pi.*g.*D)

X=D;
Y=g;



%Makes matrix one column & References rows.
G1=X;
G1(:,2)=ones(length(X),1);
delta=G1\Y;

%Slope of line
slope=delta(1,1)
%Y-intercept
intercept=delta(2,1)

%Creates line of figure graph.
X1=[0:1e-3:15*10^4]';
Y1=delta(1,1).*X1+delta(2,1);



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 

%This is a certain type of figure Matlab will draw.
figure(1)

%Clears existing graphs.
clf

%Plots command and bold blue dots.
plot(X,Y,'ob','MarkerFaceColor','b','Markersize',7)%plot the data



%Finished plotting.
hold off

%Sets background color to white.
set(figure(1),'color','white') 

%labels for the x and y axis.
xlabel('D(m)')%label the x axis
ylabel('g(m/s^2)')%label the y axis

%Average density of the earth
PE=5496.25342379935;
DS=120536.*1000;
gs=(2*pi.*G1.*DS.*PE)./3

Answer 1

[Image Analyst]

Add this to the end of your code:

% Fit a line.
coefficients = polyfit(X, Y, 1);
% Get 1000 x values
xFit = linspace(min(X), max(X), 1000);
% Get fitted y values.
yFitted = polyval(coefficients, xFit);
% Plot
hold on;
plot(xFit, yFitted, 'r-', 'LineWidth', 3);
grid on;