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1. ## STATS help PLEASE , reps for help, urgent!

Have to hand this assignment in tomorrow and i dont understand this ? at all..

Osteoporosis is a condition in which the bones become brittle due to loss of minerals. To diagnose osteoporosis, an elaborate apparatus measure bone mineral density (BMD). BMD is usually reported in standardized form. The standardization is based on a population of healthy young adults. The world health organization criterion(WHO) for osteoporosis is a BMD 2.5 standard deviations below the mean for young adults

1)What percent of healthy young adults have osteoporosis by the WHO standard

2)Women aged 70 to 79 are of course not young adults. The mean BMD in this age is about -2 on the standard scale for young adults. Suppose that the standard deviation is the same as for young adults. What percent of this older population has osteoperosis

2. ^^

3. Hint: Draw the bell curve.

This is a fairly common problem in stats, should be an example exactly like it in the book.

Sorry I can't take the time to solve it I'm headed to work out

4. Originally Posted by riprock
Have to hand this assignment in tomorrow and i dont understand this ? at all..

Osteoporosis is a condition in which the bones become brittle due to loss of minerals. To diagnose osteoporosis, an elaborate apparatus measure bone mineral density (BMD). BMD is usually reported in standardized form. The standardization is based on a population of healthy young adults. The world health organization criterion(WHO) for osteoporosis is a BMD 2.5 standard deviations below the mean for young adults

1)What percent of healthy young adults have osteoporosis by the WHO standard

2)Women aged 70 to 79 are of course not young adults. The mean BMD in this age is about -2 on the standard scale for young adults. Suppose that the standard deviation is the same as for young adults. What percent of this older population has osteoperosis
1.) The way to solve this one is through the use of DPMO as it relates to sigma level. Now, I am not sure if you covered a 1.5 sigma shift for short vs. long term data, but assuming the 2.5 sigma level contains the shift (which it probably does), that would correspond to a DPMO level of 0.0062 failed (per DPMO chart or MS Excel 1-Normdist function). So, only 0.621% have it.

2.) I'm confused with what they are saying in the problem. However, here's my guess. I believe they are saying that the high risk group of women 70-79 are 2 deviations ABOVE the mean. That would make the answer the DPMO that corresponds to a z-score of -2. That would be 97.725% that have it.

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