1) There was no statistical analysis done in this study and number not added properly.
Was there only one number or should it be 'numbers were not added correctly'? Is the problem the inclusion of the numbers, which my previous sentence suggests or were the calculations inaccurate. If the latter is the case, then I'd change 'added' to 'summed' (if it's addition) or 'calculated'
2) Lastly, It would be better if the authors could clarify the drug that being sponsored for research and the company that gives fund for the research and name of the drug that being studied.
No need for the capital in 'it would be better'
Lastly, it would be better if the authors could clarify the drug being sponsored for research, the company funding the research and the name of the drug being (though if the study is complete, then delete 'being') studied.
I'm not sure here whether you are certain that this research is sponsored. if so, then the sentence above is fine. If you aren't sure, then it would be 'clarify whether the drug is being sponsored...'