# Need Sample Size command for Graphing Calculator

David Klapheck shared this idea 2 years ago
Completed

The length command is no longer available for students to use in GeoGebra Graphing command because it can do things not appropriate on a graphing calculator such as

Length( <Arc> ) returns the arc length (i.e. just the length of the curved section) of an arc or sector.

Length( <Function>, <Start x-Value>, <End x-Value> ) Yields the length of the function graph in the given interval.

But there is one thing that the length command did that is part of every graphing calculator I have used. The sample size function. On ti-84 it is under 1-Var Stats as n=

Length( <List> ) yields the length of the list, which is the number of elements in the list.

Now that Length command is not available in Graphing calculator could you create another command for the graphing app? Size(<list>) = number of distinct elements in <list>.

Seems a little silly to have a frequencytable(true,<list>) and read the total size in the last row but not have this easily found directly.

I will be needing this for my Statistics students who use GeoGebra graphing app on exams this month.

1

The Lenght Command is already discussed in earlier posts. Use the geometry app was and is still the available option. Please don't say that your students can't use a GeoGebra app on their exams but that you want to use the particular graphing app, while developers have made other choices and offer you an alternative app.

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Would it not make sense to have a sample Size( command in the graphing app since it is standard in graphing calculators?

It is true I can have my students download the Geometry app. They don't need the table tool. The display setting on it would need to be changed each time.

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try sum(if(isdefined(element(list,k),1,0),k,1,1000) or create an specific tool for your student

I am not sure about the above comand because I do not use other than clasic

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Simple variant as user tool

using: Sum(Zip(1, N, <list>))

I think it has no restrictions versus Length(<list>)

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A work around for finding the size of list d in the Graphing app is

Sum(d^2>=0) or Sum( d>=Min(d) ). This does show off some of the capabilities of GeoGebra.

I have also started moving all of my examples from the graphing app to classic.

Any chance a limited form of the Length command will be available in the graphing app this year? Or a new Size command?

Thanks.

1

Thanks rami.

Another work around, for now, that my students can understand is n=Sum( Frequency(l1) ).

I plan to continue to use the graphing app for my statistics students who use their cell phone because it is formatted more appropriately than the geometry app. I will also augment it with the classic app for students who can use a computer.

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Sorry, we'll try and add Length() back soon

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Please try the new version v587