Question

Help! Will give out medals to those that will explain how to answer this!!! Statistics
I know what standard deviation and what mean is but...I have no clue on this one :((
he scores of students in a Mathematics examination is normally distributed with a mean of 60 and a standard deviation of 8.
a) How many percent of the examinees got scores below 44?
b) How many percent of the examinees got scores above 68?
c) How many percent of the examinees got between 52 and 76?
d) If 50 students took the examination, how many got scores above 36?

Answer 1

Are you familiar with "z-scores"?
If so, please type out the formula for z-score here:

Answer 2

or, you may use
"68-95-99.7" rule

Answer 3

which one of them you heard of before ?

Answer 4

i wonder if there is double posting going on, or if this is a site issue :/

Answer 5

"68-95-99.7" rule :

Approximately 68% of the observations fall within 1 standard deviation of the mean
Approximately 95% of the observations fall within 2 standard deviations of the mean
Approximately 99.7% of the observations fall within 3 standard deviations of the mean

Answer 6

Hello, I have just encountered z-scores while finding for the concept of normal distribution

Answer 7

I don't quite understand them, the textbook which we were asked to read only contained concepts on standards deviation and mean and things like that

Answer 8

and I was quite surprised to get such a question :(

Answer 9

this can be done using just the standard deviation and mean + 68-95-99.7 rule
zscores require u to interpret zscore table to extract areas

Answer 10

@jikanwahayaine: Either method would solve you well in answering this question. choose whichever approach is easier for you. Then we could discuss how to answer this question using the other method.

Answer 11

I'm ready to learn how +_+ please teach me :) but uhm, I'm quite new to both approach mentioned >.< D:>

Answer 12

do you know what a normal distribution curve looks like?

Answer 13

I've searched for one on "mathisfun.com"

Answer 14

it looks like a bell ? :)

Answer 15

a bell yes, and at the bottom we can measure off in units of the standard deviation