Unit test

Which graph represents a density curve, and why? O graph A only, because the curve is above the horizontal axis, and the area under the curve is 1 Graph A Ohgraph B only, because the curve is above the horizontal axis, and the area under the curve is 1 A - O both graph A and graph B, because both curves are above the horizontal axis, and the areas under both curves equal 1 w - - - - - neither graph A nor graph B, because, even though -1 0 1 2 both curves are above the horizontal axis, the area cannot be determined for graph B