Can't get this....

[Shannon70]

Hi,
I'm having trouble with this.. what exactly should I be doing with the middle parenthesis?
I keep getting 23.9, and I don't think it's right....
where ∑3S = 34
BMI=20.9

= 0.169(∑3S) − (0.0007 ∑3S²) + 0.849(BMI) + 1.260

 

[Quaid]

I'm having trouble with this.. what exactly should I be doing with the middle parenthesis?

I keep getting 23.9, and I don't think it's right....

where ∑3S = 34

BMI=20.9

= 0.169(∑3S) − (0.0007 ∑3S²) + 0.849(BMI) + 1.260

Hello Shannon:

My guess is that you're using some formula related to a Body Mass Index.

What does S represent?

Can you post the exercise statement (including instructions), and include any formulas the led to your equation.

Otherwise, you may wait to see if somebody else recognizes the context.

Cheers :cool:

 

[Shannon70]

Hello Shannon:

My guess is that you're using some formula related to a Body Mass Index.

What does S represent?

Can you post the exercise statement (including instructions), and include any formulas the led to your equation.

Otherwise, you may wait to see if somebody else recognizes the context.

Cheers :cool:

Correct, it's a body fat calculation using skinfold thicknesses.
The sum of the skinfolds is 34

Percent body fat for non-Hispanic white women = 0.169(∑3S) − (0.0007 ∑3S²) + 0.849(BMI) + 1.260


Where:

• ∑3S = sum of three skinfold thicknesses − (triceps + iliac crest + front thigh skinfolds) in millimeters (11,11,and 12)
• BMI = body mass index (should be 20.4)

Thanks!

 

[Quaid]

Correct, it's a body fat calculation using skinfold thicknesses.

The sum of the skinfolds is 34

Percent body fat for non-Hispanic white women = 0.169(∑3S) − (0.0007 ∑3S²) + 0.849(BMI) + 1.260


Where:

• ∑3S = sum of three skinfold thicknesses − (triceps + iliac crest + front thigh skinfolds) in millimeters (11,11,and 12)
• BMI = body mass index (should be 20.4)

Thank you for the clarification, but your BMI value changed above. (Typo somewhere?)


I get 23.52% body fat, using the new value BMI = 20.4

I get 23.94% body fat, using the original value BMI = 20.9


You seem to have done the arithmetic correctly; what is your concern about the result?

 

[Shannon70]

Thank you for the clarification, but your BMI value changed above. (Typo somewhere?)


I get 23.52% body fat, using the new value BMI = 20.4

I get 23.94% body fat, using the original value BMI = 20.9


You seem to have done the arithmetic correctly; what is your concern about the result?

Thanks-Yes, I gave the wrong BMI the first time. This formula is just one of about 6 different formulas to calculate body fat, and the answers are all over the table- the same input data is giving results ranging from 11% to almost 24%. I figured I must have been missing something as I didn't think the system could be so inaccurate. Thanks so much for you help!

 

[Shannon70]

Well...just quit eating pizza and sundaes

Hahahaha NEVER!!!!