The melting points of two alloys used in formulating solder were investigated by melting 21 samples of each material. The researchers want to investigate the claim the claim that the alloys have different melting points. Assume that both populations are normally distributed and have the same standard deviation. What kind of hypothesis test should the researchers do

Place several e-field sensors at a few points on different equipotential lines, and look at the relationship between the electric field and the equipotential lines. which statement is true? 1-at any point, the electric field is perpendicular to the equipotential line at that point, and it is directed toward lines of higher voltages. 2-at any point, the electric field is perpendicular to the equipotential line at that point, and it is directed toward lines of lower voltages. 3-at any point, the electric field is parallel to the equipotential line at that point.