# Power model equation for data given.

• November 26th 2012, 12:35 PM
NoIdea123
Power model equation for data given.
Im doing a workbook thats using logs and power functions. I have two questions that need to be answered that i cant get around because my booklet doesnt explain how to do it. So here goes:

The data in the table below shows the results of some baby measurements made in their first 12 months. The data can be modelled by a power function of the form y=ax^b.

Table=

Time since birth (x months)- 1,2,3,4,6,8,12
Average head circumference (y cm)- 36.6, 39.3, 41.0, 42.1, 43.7, 45.0, 46.9

A) Write your power model equation for the data given above.

B) Use your model to predict the likely head circumference of a baby at 14 months. show all working.

• November 26th 2012, 03:48 PM
skeeter
Re: Power model equation for data given.
what technology are you permitted to use?
• November 26th 2012, 03:53 PM
NoIdea123
Re: Power model equation for data given.
Excel or a graphing calculator.
• November 26th 2012, 04:20 PM
skeeter
Re: Power model equation for data given.
If your graphing calculator is a TI (83 or 84) , it will do a power regression with your data entered into lists.

I performed a power regression on my TI-83 using your data and found $y = 36.7x^{.099}$ (rounded a and b).