How much leeway will i have in suggesting a co-adviser or committee member when i am funded by a professor? I have completed master's thesis with an advisor in Industrial Engineering and I am pursuing PhD with another professor in same department. My PhD involves statistics heavily and I am not at all good with statistics. In fact I have C in two mandatory statistics courses I took in the masters program. 

Usually this lab works with a Chinese statistics professor. I find it very difficult to understand her. I find her to be very knowledgeable but are just not good at explaining things. Would it be acceptable if I asked my advisor to bring my master's advisor on board the PhD committee so that she can help me with the statistics material? He taught entry level statistics courses in masters program and helped me substantially with the statistics material of my master's thesis.

Will I have any leeway to do something like this especially when he is funding me for PhD, and what will be the best way to bring this up?
Would it be acceptable if I asked my advisor to bring my master's advisor on board the PhD committee so that she can help me with the statistics material?


You can definitely ask your advisor. Describe why you think this professor would be helpful on your committee, then see what your advisor has to say.


  Will I have any leeway to do something like this especially when he is funding me for PhD


Getting funding from someone doesn't mean they get to dictate everything about your PhD career without any input from you. It's your PhD and ultimately your responsibility to make sure you succeed. 

In fact, depending on your department rules, the decision as to who goes on your committee may very well be yours, not your advisor's. Of course, you should consult with your advisor on something like this, because part of his job is to help you make these decisions.

But you should understand that this is your research career regardless of who funds it. And even if your advisor is a great scientist and advisor and you respect his advice, you should always feel that you have "leeway" to make suggestions.


  and what will be the best way to bring this up?


Just set up a meeting with your advisor and say "I wanted to talk about my PhD committee. Here is why I think Professor X would be a valuable person to have on my committee..."

Note: I'm not commenting on whether or not your MS advisor is actually a valuable person to have on your committee - just that it's always OK to make a suggestion like this.