Are survey legitimate

I am not sure I understand your question. If you are asking whether surveys themselves are legitimate-- as in, when you hear on TV or radio that a company took a survey and found out that X, Y, or Z is true, if the survey was conducted by professionals with experience and the questions were fair and the sample size was valid, then yes you can get some useful information from a survey. Another name for a survey is a "poll" and you may have heard of the Gallup Poll or a number of other political and cultural surveys that try to measure the public's attitudes on given issues.

But if you are asking whether you can make money at home by giving surveys or grading them, no not usually. Most surveys are conducted by reputable (and professional) groups. They use their own staff to go out and ask the questions, and their staff will code the results and analyze the data. Companies that claim you can make big bucks by giving surveys are usually a scam.