Answer:
Step-by-step explanation:
Use a calculator with built-in statistical functions. The function applying here is normcdf(, the "cumulative density function."
(a) The percentage of values lying between 138 and 162 is
norm(138,162, 150, 12), which comes out to 0.683, or 68.3%.
(b) Find norm(126, 174, 150,12): 0.945, or 94.5%
(c) Find norm(126,162, 150,12); 0.819, or 81.9%
(d) Find norm(162, 174,150,12): 0.136, or 13.6%
