Well, in as much as I want to agree with what everybody has written, my experience has been different. We as Nigerians find it very difficult to follow instructions/rules and as such miss the point in most of the visa requirements.
My family and I are new immigrants and immigrated to Canada last year Sept. Bearly six months into our stay here, my wife invited her mother and she was given a visa. my wife's mum does not have any substantial amount of money in her account in Nigeria and currently retired. Her visit was entirely on us and all we had in our account was just $5000 as at that time. If your facts are consistent and you provide all that has been requested as requirement, I think Canada is a family oriented country and will issue visa to relatives, most especially parents. I have a friend that had on file that his mother was late when he was applying for his PR and now wanted to bring in the aunt as his mother after 5yrs just because he saw my wife's mother was given Visa, (can u imagine??)