I have some data samples , used histfit in matlab and did some integrated tests in matlab to test if the data is normally distributed, but i`m not convinced.
I have around 200 values in my sample
- Can I tell from the graphs if it is nor not?
- All my data has to be under the curve to be normally distributed?
Perfectly normally distributed data is in practice effectively non-existent. While one can manipulate bin widths to show many things or end up with misleading plots, your data does not look normal.
But why do you want to know? If you care about what analysis method to use, then firstly you should not care about the data (i.e. dependent and independent variables), but the regression residuals. Secondly, deviations don't necessarily invalidate a model with normally distributed error terms.