Expert: Sherman D. - 5/26/2009

Question
Hi, I was was given a practice question that will be worth 7 marks on a test. But the way I did it was too short and simple. So I was wondering if there is another way of doing it? The question is...Eldon received 72 on his first calculus test. The marks were normally distributed with a mean of 60 and a standard deviation of 8. He received 80 on the next test, which was normally distributed with a mean of 75 and a standard deviation of 6. Which was the better mark, relatively speaking?

Answer
z = (x - u)/A

sorry i didn't use the character map to send you the right symbols.

z = (72 - 60)/8
z = 8/8
z = 1

so this would be 1 above the SD

z = (80 - 75)/6
z = 5/6

so this would be 5/6 above the SD

so he scored better on the first test than on the second test.

i got my info at www.askmehelpdesk.com/mathematics/mean-standard-deviations-315491.html

sorry i had to look it up because there are certain of area of math that i'm still learning, since they didn't teach it in the high school i was in.

if that is what you did and it the one that was to short, then i don't know what your teacher wants from you.