Hi,

could anyone please explain to me how to use `inv()`

and `\`

properly to have valid results. Alse when checking with `GLM`

package basic OLS gives different results and sometimes it is way too far. It might be caused by the data but strangely.

Thanks a lot.

```
x = randn(100, 3)
y = randn(100)
```

```
julia> (transpose(x) * x) \ (transpose(x) *y) .== inv(transpose(x) * x) * (transpose(x) *y)
3-element BitArray{1}:
1
0
1
julia> (transpose(x) * x) \ (transpose(x) *y)
3-element Array{Float64,1}:
-0.13268579177064818
-0.0009498174455286444
0.06340639348585342
julia> inv(transpose(x) * x) * (transpose(x) *y)
3-element Array{Float64,1}:
-0.13268579177064818
-0.0009498174455286456
0.06340639348585342
julia> using GLM
julia> (transpose(x) * x) \ (transpose(x) *y)
3-element Array{Float64,1}:
-0.13268579177064818
-0.0009498174455286444
0.06340639348585342
julia> GLM.coef(lm(x, y))
3-element Array{Float64,1}:
-0.1326857917706482
-0.0009498174455286441
0.06340639348585342
julia> (transpose(x) * x) \ (transpose(x) *y) .== GLM.coef(lm(x, y))
3-element BitArray{1}:
0
0
1
```