Answer: 12≠6
False
Step-by-step explanation:
Supposing, for the sake of illustration, that the mean is 31.2 and the std. dev. is 1.9.
This probability can be calculated by finding z-scores and their corresponding areas under the std. normal curve.
34 in - 31.2 in
The area under this curve to the left of z = -------------------- = 1.47 (for 34 in)
1.9
32 in - 31.2 in
and that to the left of 32 in is z = ---------------------- = 0.421
1.9
Know how to use a table of z-scores to find these two areas? If not, let me know and I'll go over that with you.
My TI-83 calculator provided the following result:
normalcdf(32, 34, 31.2, 1.9) = 0.267 (answer to this sample problem)
Given:
2002 sold 1000 paperback books and 1500 hardback books for a total of 2,500 books.
2003 sold 15% more paperback books and 5% more hardback books.
1000 x 1.15 = 1,150 paperbacks
1500 x 1.05 = 1,575 hardbacks
1150 + 1575 = 2,725
2,725 - 2,500 = 225
225 / 2,500 = 0.09
0.09 x 100% = 9% choice C
