inspection of linearity of data?

Hello ! I want to check the linearity between two data set named as L_comp and L? please find attached. How can I check the trend of the following dataset? Many thanks !

Answer 1

[Chunru]

load(websave("check_linearity.mat","https://www.mathworks.com/matlabcentral/answers/uploaded_files/1167363/check_linearity.mat"))
whos

  Name          Size            Bytes  Class     Attributes

  L           122x1               976  double              
  L_comp      122x1               976  double              
  cmdout        1x33               66  char                

% use curve fitting toolbox
f  = fit(L, L_comp, 'poly1')

f = 
     Linear model Poly1:
     f(x) = p1*x + p2
     Coefficients (with 95% confidence bounds):
       p1 =     -0.2864  (-0.3991, -0.1736)
       p2 =      0.2222  (0.199, 0.2455)

plot(f, L, L_comp)

[Khan Muhammad Adeel Khan]

Many thanks! Could you please explain the output a bit ? How we can save the slope, and then test all the slopes within each group against 0 via the ttest function?

Linear model Poly1:

f(x) = p1*x + p2

Coefficients (with 95% confidence bounds):

p1 = -0.2864 (-0.3991, -0.1736)

p2 = 0.2222 (0.199, 0.2455)