4.56. The curve for a normal distribution with mean p and standard deviation a has mathematical formula f(y) = (>'-M)2

/(2^2

)_

•J2tti ira Show that this curve is symmetric, by showing that for any constant

c, the curve has the same value ni y - p + c as at y = /x —

c. (The integral of

/(y) for y between p + za and oo equals the tail probability tabulated in Table A.)