1. K

    Is 3% difference significant in an experiment?

    I am trying to see if certain change in a survey will impact the response rate. I sent the survey to 3277 people in the experimental group (with the change implemented) and to 3253 in the control group (without the change implemented). In the first group 22% of people filled the survey...
  2. M

    Sampling Q - why can't we replace non-responders by randomly selecting new ones?

    We are planning a survey of schools to get state estimates of substance use among youth. We are doing a two-stage survey, where the first stage is a PPS random selection of schools, and the second stage is random selection of classrooms (then the students in the classroom are surveyed). We...