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Tamooma | 22:36 Mon 08th Aug 2016 | Quizzes & Puzzles
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The mean is μ=15.2 and the standard deviation σ=0.9 . Find the probability that χ is greater than 15.2
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0.5000
22:41 Mon 08th Aug 2016
0.5000
I'd love to know how you worked that out.
What distribution you are using (probably normal) and the confidence level?
Which quiz is this?
How confident are you that mac is right?
I think the value of σ is a red herring here
Jackdaw- I think mac is simply saying that if it's a balanced distribution (like the normal bell curve or a uniform distribution then half the values will be above the mean and half below the mean (give or take some that are exactly on the mean)
It's very confusing when the odds are evens! :-)
I thought the question seemed odd.
I think the question should be:

Assume that X has a normal distribution, and find the indicated probability.
The mean is µ= 15.2 and the standard deviation is σ = 0.9.
Find the probability that X is greater than 16.1.

http://www.compton.edu/facultystaff/jmmartinez/docs/Math-150-Spring-2015/Math-150-E3-SP15-Practice.PDF
Maybe the question was right. Variations on this question seem common on US exam papers.
Here's the same Q that Tamooma asked

59) The mean is μ = 15.2 and the standard deviation is σ = 0.9.
Find the probability that X is greater than 15.2.

A) 0.5000 B) 1.0000 C) 0.9998 D) 0.0003

The answer was indeed A} 0.5

http://www.brazosport.edu/faculty-staff/directory/CalinAgut/Documents/Practice%20PDF%20Statistics/Review%202,%20Stat%20(OK).pdf

Jackdaw

Normal distribution is symmetric; its mean \mu = median.
Hence we have \Pr\{X < \mu\} = \Pr\{X > \mu\} = 0.5

See 16:38

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