Michigan's Presidential Primary is scheduled for Feb. 28. Ahead of election day, The Glengariff Group, Inc. conducted a 500-sample, live operator telephone survey of registered Michigan voters likely to vote in the state's Feb. 28 Republican Presidential Primary Election. The survey was conducted on February 11-13 and has a margin of error of +/-4.38% with a 95% level of confidence.  This survey was commissioned by the WDIV Local 4 and the Detroit News.