The mean and SD of a certain group of 1000 high schoold grades, that are normally distributed are 78% and 11% respectively. (i) Find how many grades were above 90%? (ii) What was the highest grade of the lowest 10? (iii) What was the semi-interquartile range (Quartile deviation)? (iv) Within what limits did the middle 900 lie?

MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
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The mean and SD of a certain group of 1000 high schoold grades, that are
normally distributed are 78% and 11% respectively.
(i) Find how many grades were above 90%?
(ii) What was the highest grade of the lowest 10?
(iii) What was the semi-interquartile range (Quartile deviation)?
(iv) Within what limits did the middle 900 lie?
Transcribed Image Text:The mean and SD of a certain group of 1000 high schoold grades, that are normally distributed are 78% and 11% respectively. (i) Find how many grades were above 90%? (ii) What was the highest grade of the lowest 10? (iii) What was the semi-interquartile range (Quartile deviation)? (iv) Within what limits did the middle 900 lie?
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