with the question given above,
(a) P(262= P[z < (832 - 475)/85] - P[z < (262 - 574)/95]
= P(z<3) - P(z<-3)
looking at the z-score table, we find
= 0.9987 - 0.0013
= 0.9973
= 99.7%
(b) P(x>737) = 1 - P(x <=737
= 1 - P[z<= (737 - 547)/95]
= 1 - P(z<= 2)
= 1 - 0.97725
= 0.02275
= 2.3%
(c) P(x < 262) = P(z< -3
= 0.0013
= 0.13%
(d) P(452= 0.97725 - P[z < (452 - 547)/95
= 0.97725 - P(z<-1)
= 0.97725 - 0.15866
= 0.81859
= 81.9%