Question

type your answer in exactly as one of the following: population, sample, srs, systematic, stratified, cluster, multistage, voluntary, convenience, survey, observation, experiment, undercoverage, response, nonresponse (answer the multiple choice with a uppercase letter) 1) source of bias in which some groups of populations are left out of the selection process 2) source of bias in which people choose to respond and usually only people with very strong opinions respond

Explanation:

1. Undercoverage is the bias where certain population groups are excluded from selection.
2. Voluntary bias occurs when people choose to respond, often those with strong opinions.

Answer:

1. undercoverage
2. voluntary