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# Thread: Statistics Problems (Normal Distribution) (Reps)

1. ## Statistics Problems (Normal Distribution) (Reps)

I know I have to use the equation "Z = x - mean/standard deviation" and then look up the AUC in a table for all of these questions, but all these problems are different. And if anyone knows of any good statistics websites, please link to it!

The brain weights of a certain population of adult Swedish males follow approximately a normal distribution with mean 1,400 g and standard deviation 100g. What percentage of the brain weights are:

a) 1325 and 1500g?
b) 1325g or more?
c) 1500g or less?
d) between 1475 and 1600g?

2. So basically what im getting from this post is that you are telling us that you are coming out of the closet?

3. Originally Posted by The Prime Nip
I know I have to use the equation "Z = x - mean/standard deviation" and then look up the AUC in a table for all of these questions, but all these problems are different. And if anyone knows of any good statistics websites, please link to it!

The brain weights of a certain population of adult Swedish males follow approximately a normal distribution with mean 1,400 g and standard deviation 100g. What percentage of the brain weights are:

a) 1325 and 1500g?
b) 1325g or more?
c) 1500g or less?
d) between 1475 and 1600g?
For example: (1400 - 1325) / 100 = .75 std deviations from the mean. Find the Z statistic/value for that ****. In this case .7734 (its a left tailed test)

The (1400 - 1500) / 100 = 1 std deviations = 0.1587 (right tailed). Subtract that **** and you get....(.7734 - .1587) = .6147

Just thing logically and use this website http://www.tutor-homework.com/statis...cs_tables.html

Note: I am fairly buzze dand I accept no responsibility for the correctness of your answers

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