How can I fit a line to values and plot it on the same plot as those values?

I have 70 different temperatures that I need to plot over the course of 70 years. I was able to do that but I also have to fit a line to those values and plot it in the same plot. I tried using polyfit but when I tried to plot that it would remove my intitial plot.

Here is a picture of what I need to do

Answer 1

[Akira Agata]

Maybe I guess the usase of polyfit, polyval or hold function in your code is incorrect. How about the following?

% Sample data
Time = 1948:2017;
Temp = (20:0.01:20.69) + rand(1,70);

% Fit with 1st order polynomial
p = polyfit(Time,Temperature,1);
predTemp = polyval(p,Time);

% Plot the result
figure
plot(Time,Temp)
hold on
plot(Time,predTemp)

[Samy Ben Thabet]

It worked thank you!