Error Using Plot: Vectors Must Be The Same Length

Hi, I'm getting this error when trying to plot my 2 graphs: Vectors must be the same length. I am very new to matlab and I understand this is a common problem but couldn't figure out how to change my code so it works just by looking at other people's more complicated situations of the same error. It is a (22875x4 double)

This is my code (where DataPoints is the name of my file):

clc 
Fs=1000
variable1=(DataPoints);
variable2=0.01:Fs/10000:length(variable1)*Fs/1000
variable3=(DataPoints);
figure(1);
plot(variable2,variable3)

variable4=variable1;
variable5=length(variable1);
variable6=Fs;
[P1,F1]=pwelch(variable4,variable5,variable6);
Figure(2);
Plot(F1,P1)

[Torsten]

And do you get the same output for

numel(variable2)
numel(variable3)

?

The error message says: no. So change variable2 accordingly (e.g.

variable2 = linspace(0.01,numel(variable3),numel(variable3))

[Aphile]

I just tried this and it says "Unrecognizable function or variable."

Answer 1

[Matt J]

Check the lengths of the variables you are plotting:

whos variable2 variable3 P1 F1

There is no gaurantee that I can see, based on the code you've shown, that variable2 and variable3 would be the same length.

[Aphile]

I don't think they are as this is data from a dynamic test and im trying to plot a psd as well as time-acceleration graph.

[Matt J]

If they are not the same length, what does it mean to you to "plot" them? A plot consists of coordinate pairs (x,y). If the inputs are not vectors with the same number of elements, how can you create pairs?