Linear Function for modelling child's height, head circumfer

[Jag]

Hello everyone,

This is my first time needing help with a math problem and I hope you guys will be able to help me with this as I was unable to find any information in my textbook or online in order to solve this problem. Its a multiple part question and if you can explain to me how to solve it and do each step, I would be more than graciously thankful for the help. If you can also provide an answer for each part, that would greatly help me with this homework problem as I'm utterly lost and daunted by looking at this problem. Thank you very much in advance for helping me out here.

A pediatrician wanted to estimate a linear function that relates a child's height, H, to his or her head circumference, C. She randomly selects nine children from her practice, measures their height and head circumference, and obtains the data shown on the right. Let H represent the independent variable and C the dependent variable. Answer parts (a)-(e) below.

H C
24.75 16.3
25.25 16.8
24.5 16.8
27.25 17.5
26 17.2
26.5 17.4
26.25 17.2
26.25 17.4
27 17.4

(a) Use a graphing utility to draw a scatter diagram.

(b)Use a graphing utility to find the line of best fit to the data. Express the solution using function notation.

f(x)= ____

(c) Interpret the slope.
(Lists 4 possible answers, multiple choice)

For every

A. 0.373 inches taller a child is, the circumference of his head is one inch larger.

B. 0.373 inches taller a child is, the circumference of his head is one inch smaller.

C. inch taller a child is, the circumference of his head is 0.373 inches smaller.

D. inch taller a child is, the circumference of his head is 0.373 inches larger.

(d) Predict the head circumference of a child that is inches tall.

The head circumference is predicted to be ___ inches.

(e) Predict the height of a child whose head circumference is 17.1.

The child is predicted to be ___ inches tall.


Thank you once again for taking the time to help me in my education process.

~Jag

 

[wjm11]

Re: Linear Functions

A pediatrician wanted to estimate a linear function that relates a child's height, H, to his or her head circumference, C. She randomly selects nine children from her practice, measures their height and head circumference, and obtains the data shown on the right. Let H represent the independent variable and C the dependent variable. Answer parts (a)-(e) below.

H C
24.75 16.3
25.25 16.8
24.5 16.8
27.25 17.5
26 17.2
26.5 17.4
26.25 17.2
26.25 17.4
27 17.4

(a) Use a graphing utility to draw a scatter diagram.

(b)Use a graphing utility to find the line of best fit to the data. Express the solution using function notation.

Jag,

Here’s the deal: I can’t teach you all of this online, but the bottom line is that you need to know how to use your calculator. I’ll assume you’re using something along the lines of a TI-83 or TI-84.

You need to enter the data for H and C into you lists. Put H data into List 1 and C data into List 2.

Then you need to find (somewhere in the menus) “LinReg” (I think that’s how it’s listed.). The LinReg function will calculate “a” and “b” values for you (the slope and y-intercept of the line).

This is a “best fit” line for your data. If you put this line into your “y editor” and plot it along with a scatterplot of your data points, you’ll find the line models the data nicely.

Hope that helps.

 

[Jag]

Re: Linear Functions

Hmmm.. I'm using a TI-84 Silver Edition but I'm still rather lost here. I'm quite new to this and the teacher is rather un-helpful in this situation. If you could please go a little bit more into depth or if you know of a website that could provide a good reference, I would be very happy.

 

[wjm11]

Re: Linear Functions

I'm using a TI-84 Silver Edition

I don't have a TI-84, but I think the List editor may be above the Stat key. You need to read your owner's manual.

You might also try the TI website to search for calculator info there.

After learning how to enter lists, the next thing you need to find is "linear regression." It may be Under one of the "Math" menus.

 

[Deleted member 4993]

Depending on your career aspirations, it may be useful for you to learn to use Microsoft Excel to do these types of problems.