# 3 sigma

Students' performance scores in a statistic test have a mean of 70 and a standard deviation of 4.0. The scores obtained can be modeled by a normal distribution. Find the probability that the score of a randomly selected student is

i. more than 80 marks

ii. less than 65 marks

Find also the number of students who scored above 80 marks if a total of 1200 students sat for the test.

i. more than 80 marks

ii. less than 65 marks

Find also the number of students who scored above 80 marks if a total of 1200 students sat for the test.

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