IA Type II - Fish Production

[dessskris]

@3bbasi12

you are asked to combine functions so I guess you could just model a function for each table.

@Mija

I know right?

for the third one... I guess we could go with cosine although it still won't really fit well.

good usage of technology btw

[3bbasi12]

@Desy Glau: yeah i thought of doing that too! thanks for your help. What do you think the model for the third table will be? Its very random.

[dessskris]

cos maybe? I really don't know sorry, it's too random I can't think of a function that actually fits well

[timmotytimmoty]

I don't understand the first question!!!! How should I defined variables and discuss parameter if I have only data without any model?!

Plot the data points? Is that mean to create a model?

So what kind of formula should use in this model? Sine

[dessskris]

define variables simply means something like let x be mass, let y be year, or something along those lines.

i can't comment much about parameters as i'm not so sure what it actually is, but if i were you i'd introduce my parameters when i start to model the function. the order of you answering the questions doesn't matter much as long as you include everything they want to see in your portfolio.

plot the data points means draw a graph using your data.

the formula... I'm not sure. read the whole thread to check out what people said about it.

[timmotytimmoty]

On my GDC, I've wrote in L1 the year, and L2 the amount of fish production. After that, I tried to find the regression, but the number of a, b, or c are very high, and it is so impossible. I guess in L1 shouldn't be the year. Any suggestion how should I write on my GDC?

[dessskris]

you can't simply plot the data points to get the best fit regression, because there isn't any actually. split the data into probably 3 parts and use a combination of functions.

I'd put years on the x axis and mass on the y axis.

[timmotytimmoty]

Yes, You are definitely right! I've also found out that the data is not possible to represent in one function. I'm wondering what function can I use in part from 1980-1989? Any suggestion? Is the rest can use SinReg?

[timmotytimmoty]

How should I write in my calculator? SinReg L1,L2? (Which L1 is the year, 1981, 1982, 1983......, L2 is the value. mass of fish production

[timmotytimmoty]

Is anyone who can tell me what function can be used in the second graph(second table)?

[timmotytimmoty]

Is anyone who can tell me what function can be used in the second graph(second table)?

[Peter]

It seems the model function to fit the data points is a periodic function of the form similar to:

y = a sin(bx + c) + d

However, the amplitude of the function decreases when x increases. There is a hint saying that "consider a combination of functions".

Anyone has idea on what combination of function it is to get a periodic function of decreasing amplitude?

Peter

[dessskris]

I'm not very sure either sorry.

the best thing I could think of is:

y=ax*sin(bx+c)+d

for increasing amplitude.

and

y=a*sin(bx+c)/x+d

for decreasing amplitude.

maybe you could play with it. try plotting y=x*sinx and y=10*sinx/x if you'd like to see the rough shape.

[tomppa]

Anyone got any new ideas on how to find the suitable functions for each table.

For the first 2 I have found a polynomial equation that fits the points almost exactly.

However, for the third one i cant seem to find one. Is there other ways of doing the first 2 without

using polynomial equations but by using sin/cos or something similiar any help would be much appreciated.

[dessskris]

have you read this post --> ? it's the best clue I could give I'm sorry I'm clueless for this task

[megailves]

the third section could be a sine function. if you use a graphing program than copy the sine function for the second section and then start changing the values for a,b,c and d to fit it to the data points.

[hana nana]

Anyone got any new ideas on how to find the suitable functions for each table.

For the first 2 I have found a polynomial equation that fits the points almost exactly.

However, for the third one i cant seem to find one. Is there other ways of doing the first 2 without

using polynomial equations but by using sin/cos or something similiar any help would be much appreciated.

what is the degree for the polynomial eq. dat u used??

[haures]

I dont get how this works. Can we define a function for each table? Or do we have to combine all the functions together? And if so, how do we do that?

From the question, it stated 'plot the data points from the table on a graph. so i would suggest only one graph...I'm not conformed yet, though.you can use Excel or Geogebra...I still don't know what suitable models should I use that have similar trends...I wish someone colud help me on this...

[porridge9923]

@3bbasi12

you are asked to combine functions so I guess you could just model a function for each table.

@Mija

I know right?

for the third one... I guess we could go with cosine although it still won't really fit well.

good usage of technology btw

I was thinking of using sin(x)/x. but i could not figure out how can i combine the functions together? any ideas?

[pinkiebloo]

Data from the first table:

Looks like tangent graph. I suggest modelling a tangent function whose general formula is y=a*tan(bx+c).

Data from second table:

Quite random, but it still looks like a sine function with general formula y=a*sin(bx+c) where a is negative.

Data from third table:

I honestly don't know! It's very random. The easiest would be cos though. But I'm not sure.

Hi.

I just wanted to ask, the data that you are referring to, is it the data from the total mass of fish caught in the sea or is this data from the fish farms? sorry, im kinda confused :/

thanks.