6. You wish to know whether, on average, GW students feel more safe from Covid-19 under a "mask required" policy than under a "mask optional" policy. A random sample of GW students is selected and measured twice: four weeks ago (when GW had a mask optional policy) and three weeks ago (when GW resumed a mask required policy). Each person in the sample was asked the same question at both points in time: "On a scale of - 2 (very unsafe) to +2 (very safe), how safe do you feel from Covid-19 infection?". The mean "mask required" score was 0.5; the mean "mask optional" score was 0.1; and the P(T