I have a data-set that contains 251 data points. I used minitab software to test for normality and first plotted a histogram which gave the result as under.
The above plot resembles an almost a normal distribution.However when i plot a PP Plot using Anderson-Darling test i get the significance level below 0.005 which makes me reject the null hypothesis i.e the distribution is normal.
Below is the attached PP plot.
Why are the two plots giving different conclusions ? Is my data normal ?