The marks obtained in mathematics by 1000 students are normally distributed, with mean 78% and standard deviation 11%. Determine (i) How many students got marks above 90% (ii) What was the highest mark obtained by the lowest 10% of the students?

The marks obtained in mathematics by 1000 students are normally distributed, with mean 78% and standard deviation 11%. Determine (i) How many students got marks above 90% (ii) What was the highest mark obtained by the lowest 10% of the students?

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

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Question

The marks obtained in mathematics by 1000 students are normally

distributed, with mean 78% and standard deviation 11%. Determine

(i) How many students got marks above 90%

(ii) What was the highest mark obtained by the lowest 10% of the

students?

Features Features Normal distribution is characterized by two parameters, mean (µ) and standard deviation (σ). When graphed, the mean represents the center of the bell curve and the graph is perfectly symmetric about the center. The mean, median, and mode are all equal for a normal distribution. The standard deviation measures the data's spread from the center. The higher the standard deviation, the more the data is spread out and the flatter the bell curve looks. Variance is another commonly used measure of the spread of the distribution and is equal to the square of the standard deviation.

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