In addition, it is sometimes possible to monitor certain characteristics of the animals. The length of an alligator can be estimated accurately from aerial photographs or from a boat. However, the alligators weight is much more difficult to determine. The example below provides data on the length (inches) and weight (pounds) of alligators captured in Florida. Develop a model in which the weight of an alligator can be predicted from its length. Show all of your thinking.

Question

anonymous · Answer

Length                     Weight 

58                           28
61                           44
63                           33
68                           39
69                           36
72                           38
72                           61
74                           54
74                           51
76                           42
78                           57
82                           80
85                           84
86                           83
86                           80
86                           90
88                           70
89                           84
90                           106
90                           102
94                           110
94                           130
114                         197
128                         366     
147                         640

anonymous · Answer

Can anyone help out? Because some assistance would really be appreciated.

anonymous · Answer

@Hero @amistre64 @ybarrap Anyone? Please?

anonymous · Answer

plot all your data points, then estimate a line

anonymous · Answer

or search for a linear regression calculator

anonymous · Answer

What does it mean by develop a model? What am I supposed to do for that? It says to show all my work but how and what?

anonymous · Answer

Can anyone assist? I desperately need help and soon. This assignment does have a due date and I really need help in order to finish.

anonymous · Answer

develop a model means find an equation

amistre64 · Answer

excel has a trendline feature

my ti83 has a linear regression function as well as some fancier regression functions.

if this is a stats class ... you most likely have a program available to you to work with the data set.  Statcrunch maybe?

anonymous · Answer

Nope, no mention of any program. My course doesn't explain a lot of things or offer much assistance often enough.

Find an equation - what equation? How? I'm sorry, I'm rather dumb and I'm confused.

amistre64 · Answer

what sort of programs do you have at your disposal?  excel perhaps?  do you have a fancy-schmancy graphing calculator?  because doing this by hand would take about 3 weeks to complete

amistre64 · Answer

we could develop a linear equation which may or may not best fit the data but is the "simplest" to create.  It would require knowing:  the mean length, the mean weight, the sum of the lengths, the sum of the weights, the sum of the square of the weights, and the sum of the products of length and weight.

amistre64 · Answer

once we have all that information we can construct a linear equation as:$$\hat y=\frac{n\sum xy-\sum x\sum y}{n\sum xx-\sum x\sum x}(x-\mu_x)+\mu_y$$

anonymous · Answer

I have a graphing calculator.

anonymous · Answer

I'm sorry, all those things just went right over my head. What?

amistre64 · Answer

see why it would take 3 weeks lol

is your calculator a ti83 or similar?  i have a ti83

amistre64 · Answer

if you have a ti30 then the process is tedious, but then the ti30 isnt a graphing calc so i dont know why i would even bring that up

anonymous · Answer

I have a casio fx-9750gII graphing calculator

amistre64 · Answer

bummer ... i got know idea how that one would work :/

do you have lists that you can fill in with it?

amistre64 · Answer

http://www.youtube.com/watch?v=KPEEVdkA7Wk this might be useful to you

anonymous · Answer

what kind of lists? like entering numbers in the kind of list that you make into a graph kind of list?

amistre64 · Answer

yes

amistre64 · Answer

menu, stat option, ... looks like the lists just pop up for you after that

just fill them in with the dataset they provided

anonymous · Answer

I did that. now what?

amistre64 · Answer

you tube says to select a graph, and itll scatterplot it for you;  then calc gets you to the regression options

amistre64 · Answer

when i use excel i get this:

the scatter plot looks like an x^2 is a best fit model.

anonymous · Answer

That's what I got on my calculator. It curves up like that and everything.

amistre64 · Answer

the exponential is a pretty nice fit too,  does it ask you for a specific type of curve to model?  line, polynomial, exponential, etc ?  or are you left to your own judgement for that?

amistre64 · Answer

id go with the poly x^2 or the exponential ...

anonymous · Answer

All it says is this: Develop a model in which the weight of an alligator can be predicted from its length. Show all of your thinking.

anonymous · Answer

So, I am confused. How am I supposed to like say my answer? The whole develop a model thing? Do I like say that the exponential is a good fit for the model and that's my answer? or...?

anonymous · Answer

Should I also include the formula thing for the x^2 curve thing which is y=ax^2+bx+c ? (I think that's what it is anyway. That's right isn't it?)

anonymous · Answer

@JJ_Stark  do u take chemistry?

anonymous · Answer

Yes @nannaberry

anonymous · Answer

can i tag u?

amistre64 · Answer

i would say something like, the scatterplot suggests that a linear correlation is not applicable, and that it suggests a quadratic relationship.  In my opinion, a quadratic function model best fits the data for predictive purposes.

anonymous · Answer

Thank you so much. You have been so incredibly helpful(:

anonymous · Answer

@JJ_Stark would u mind comin to my page now :)