Linear Regression not working

I'm trying to plot the same data multiple times but with a different degree of curve each time. Every time I try, the code runs through fine, but my plot does not show any line fit at all, it just shows my data points.

here is my current code.

X =

NaN

0.2200

0.3000

0.4400

0.4900

0.7000

0.8000

0.9000

1.1000

1.0000

1.1500

1.2000

1.2200

1.2600

1.2500

1.2700

1.2000

1.2200

1.2600

1.2000

1.2200

1.2600

1.2000

1.2200

1.2600

1.2500

t =

NaN

0

4

7

10

13

16

22

25

30

33

36

40

48

51

55

60

80

100

120

140

160

180

200

220

240

x=(t);

y6=(X);

% First Degree

subplot(1,3,1);

p=polyfit(x,y6,1);

f=polyval(p,x);

plot(x,y6,'o',x,f,'r-')

legend('data','linear fit')

% Second Degree

subplot(1,3,2);

p=polyfit(x,y6,2)

f=polyval(p,x)

plot(x,y6,'o',x,f,'r-')

% Third Degree

subplot(1,3,3);

p=polyfit(x,y6,3)

f=polyval(p,x)

plot(x,y6,'o',x,f,'r')

Answer 1

[Reshma Nerella]

In the plot command,

plot(x,y6,'o',x,f,'r-')

you didn’t specify any line style, so you are getting only the data points

You may use the following to display the line

 plot(x,y6,'-o',x,f,'r-')  % specify line style along with marker.

Refer the following link for documentation of plot

https://www.mathworks.com/help/matlab/ref/plot.html[SP1]