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## #1 Help Me ! » Z-score problem (percentile related) » 2013-05-04 05:43:33

aric
Replies: 1

plz help me. solution to the problem with fig. would be great. i'm trying to understand rather than just solve problems.

1. Assume that IQ scores are normally distributed with mean 100 and SD 15. Find the value which is the IQ separating top 30% and bottom 70%.

2. Let weight of men are normally distributed with mean 172 lbs and standard deviation 29 lbs. Find the value of the weight (X) which separate the top 0.5% with the bottom 99.5% of the weight.

## #2 Help Me ! » need some help plz » 2013-05-03 02:15:49

aric
Replies: 5

birth weight in US are normally distributed with mean of 340g and a strandard deviation of 45g. If a hospital plans to set up observation condition for the lightest 7% of the babies, what weight is used for the cutoff separating the lightest 7% from the others?