İ can not access an exercise

Hi Azad,
sorry to hear you're experiencing this issue!
The exercises in the courses are unlocked when you've watched the corresponding theoretical lecture in the Lessons Tab first.
If you've already seen the Cross Table and Scatter plot lesson:
Statistics | 365 DataScience
and you're still unable to access the exercises, could you be a bit more specific about the problem you're experiencing?
For instance:
Is there a problem with downloading the resources?
Is there a problem with an empty zip file, or similar?
Is there an error message on your screen or an empty web page?

Thanks a lot in advance!
Best,
365 Eli