When using a repeated measures design, researchers must control the potential threat to internal validity referred to as?

Read the paragraph and answer the question that follows: the town of belmond, iowa, needs to add weather sirens. the loud and steady wail would warn citizens of approaching danger. if past history is an indication, the sirens will save hundreds of lives. with a prediction of a deadly storm season, the alert which sentence should be revised to eliminate redundancy? the town of belmond, iowa, needs to add weather sirens. the loud and steady wail would warn citizens of approaching danger. if past history is an indication, the sirens will save hundreds of lives. with a prediction of a deadly storm season, the alert system is needed immediately.