Consider a binomial experiment with n trials and r successes. To construct a test for a proportion p, what value do we use for the sample test statistic? a) 2r / n
b) (r / n)2
c) n / r
d) r / n

Idon't see any graph, however the graph of the function : f(x) = x²-2x+3 is a parabola: 1) open upward (since a> 0)2) it intersects y-axis in 3 (y=3)3) its axis of symmetry is x = +1 ( -b/2a)4) it's minimum is y = -2, so its vertex is (1,-2)5) it doesn't intersect the x-axis since discriminant < 0