SOLUTION: Let x be the number of courses for which a randomly selected student at a certain university is registered. The probability distribution of x appears in the following table.
x 1 2
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x 1 2
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Question 1031560: Let x be the number of courses for which a randomly selected student at a certain university is registered. The probability distribution of x appears in the following table.
x 1 2 3 4 5 6 7
p(x) 0.02 0.03 0.09 0.25 0.39 0.17 0.05
It can be easily verified that the mean value of random variable x = 4.67 and standard deviation of random variable x = 1.21.
(a) Because 4.67-1.21 = 3.46, the x values 1, 2, and 3 are more than 1 standard deviation below the mean. What is the probability that x is more than 1 standard deviation below its mean?
P(x <4.67-1.21 ) = 0.000054
its incorrect but what i did was multiply the probabilities of the corresponding x values that was said to be more than one deviation
Your error was in multiplying the probabilities. You need to add them. The probability of 1, 2, or 3 is 0.14
John
My calculator said it, I believe it, that settles it
