Create multiple regressions for each group of data

Hello everyone,

I am trying to divide my table data into groups and calculate regression coefficients for each group using the market return and a constant as explainatory/independant variables and the stock market return as the dependant variable.

I have preceeded as follow:

Work = readtable('Begin Work.xlsx');

Work.Groups = findgroups(Work.Numero);

Work.Ones = ones(length(Work.MarketReturn),1);

%X = splitapply(@(x1,x2,y) regress(y,[x1 x2]),Work.Ones,Work.MarketReturn,Work.StockReturn,Work.Groups);

However, I get the following error message:

Error using splitapply (line 132)

The function '@(x1,x2,y)regress(y,[x1,x2])' returned a non-scalar value when applied to the 1st group of data.

To compute nonscalar values for each group, create an anonymous function to return each value in a scalar cell:

@(x1,x2,y){regress(y,[x1,x2])}

Error in BeginWork (line 20)

X = splitapply(@(x1,x2,y) regress(y,[x1 x2]),Work.Ones,Work.MarketReturn,Work.StockReturn,Work.Groups);

Can anyone please help me with this issue? Or recommend another way to calculate the regressions?