I'm a little confused. Many people have answered you with "No you don't need a visa" to go to Canada and join your sister on a tour. However, although I see your sister lives in Canada (making her a Canadian citizen or permanent resident), I did not see anywhere that you tell us YOUR nationality.
There are about 35 countries that are part of the "Visa Waiver Program", meaning that you do not need a travel visa to come to Canada if you are a citizen or permanent resident of one of those countries.
But if you are a citizen of a country listed on the website below, then you WILL likely need a visa to enter Canada.
http://www.cic.gc.ca/english/visit/visas…
Also, you mention you will be joining her on a tour that "visits different countries". Do you mean that the tour originates in Canada and takes you to OTHER countries, like USA, Mexico, Peru, Brazil, etc? If so, then you MAY need a visa to enter some of those countries.
Whether you need a visa or not to enter Canada (and any other country) is based entirely on YOUR nationality, not your sister's. You should advise people where you are living, what country's passport you are carrying, and then we could give you accurate information on whether you need a visa or not.