model for fitting polynomial of degree 3

Hi, i want to use 'fitlm' for fitting polynomial of degree 3. Is there some builtin name for the model? For example, for degree 2, matlab used model 'Quadratic'. I tried 'Quartic' but it did not worked.

Answer 1

[John D'Errico]

Just read the help.

x = rand(10,1);
>> y = rand(10,1);
>> D = dataset(x,y);
>> fitlm(D,'poly3')
ans = 
Linear regression model:
    y ~ 1 + x + x^2 + x^3

Estimated Coefficients:
                        Estimate                SE                  tStat                 pValue      
                   __________________    _________________    __________________    __________________
    (Intercept)     0.883325330921357    0.269610952016709      3.27629617533717    0.0169006334507573
    x              -0.905689721171103     2.50947007046528     -0.36090875592837      0.73053441711432
    x^2              2.97715513265619     5.78699413259576     0.514456221043511     0.625326610386953
    x^3             -2.49404374290891     3.78096082734174    -0.659632261956649      0.53397526842927

Number of observations: 10, Error degrees of freedom: 6
Root Mean Squared Error: 0.182
R-squared: 0.222,  Adjusted R-Squared: -0.167
F-statistic vs. constant model: 0.57, p-value = 0.655

I could also have written the model as:

fitlm(D,'y ~ 1 + x + x^2 + x^3')

which produces the same result.

[Sumera Yamin]

many thanks