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Adding a statistics package

Module 2 Session 7

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Learning Objectives Recognise the limitations of any software

even Excel!

Introduce statistics packages in general using Instat as a simple example

Explain the reasons for adding a statistics package

at this stage in the training

Show how easy it is to use a statistics package hence give confidence to students that they could easily use another package later, if needed

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Contents Review of use of Excel Problems with Excel for statistics

all packages have limitations

Adopting a flexible software strategy Why do more? Instat - an example of a statistics package What are statistics packages? Why were they scary?

and are not now

Practical, then brief discussion

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Use of Excel for statistics

Used Excel for descriptive statistics tables and graphsexploration and summary

Needed an add-in for effective use Summary of EXCEL for Statistics

Data manipulation very goodPivot tables very goodGraphics all rightVery “visual” environment

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Now need to do more

Process multiple response questions Produce tables, with weights Cope with missing values and zeros

Excel is reaching its limits It is a “jack of all trades” It is serving us well We can add other software to our “toolkit” And still use Excel when appropriate

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Another problem with Excel

Software should give the right answer We show that Excel did not

though SSC-Stat is OK Give the mean and standard deviation of:

1 2 3 4 5mean = 3 s.d. = 1.58

What is the mean and s.d. if we add 10? 11 12 13 14 15

mean = 13 s.d. = 1.58 again

* Check you understand that this is true

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Standard deviation in Excel 2000

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Conclusions from this problemSome statisticians argued

If answers were sometimes wrong, how can you trust Exceltherefore use different software for statistical applications

Our viewData where you see problems are very oddYou should notice when you get such odd dataSo continue with Excel for descriptive statisticsBut switch to statistical software for more complex descriptive analyses and for modelling

So introduce statistics packages at this pointEarlier - SSC-Stat was a first exampleof a very, very simple statistics package

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Mixing software This used to be difficult

for statistical applications because transferring data was messy and each package had its own commands

Now it is easy Windows software is all similar Menus and dialogues replace commands These dialogues are similar in most packages

And similar to those already in SSC-Stat An example of a simple statistical package

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A familiar dialogue in SSC-Stat

There are similar dialogues in any statistics package

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So

A statistics package is introduced

We use new softwareA simple package called InstatDesigned as a first statistics packageAnd to assist in teaching conceptsIn Module 4

We introduce a more powerful statistics packageCalled STATA

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Why Instat? A simple general statistics package

and therefore easy to learn to use Designed to support teaching statistics

To show the value of using the computer to support the teaching of statistics

Designed as a “stepping stone”To show how easy it is to use any statistics packageSo you can easily add others (like Stata) when you need

It also has a special menufor the analysis of climatic datawhich is a small component of this training

You can distribute Instat freelyin your country

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Why Instat continued You also learn:

It is easy to move from one Windows package to another

This is useful in Module 4, where you will use another statistics package

Once you have used two statistics packages If later, you need to use further statistics packages you should find they are simple to learn hence you no longer need a special course

And you can work with partners who use different packages

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Spreadsheet view of data

Results in different type of window

Names for columns

Data start in row 1

Key menus are Manage, Graphics, and Statistics - compare with SSC-Stat

INSTAT Windows

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What is a statistics package?

It is essentially a column calculator like Excel when the data are in “list format” Some results are on the previous slide

Menus are like those in SSC-Stat Manage, Graphics, and Statistics in Instat Manipulation, Visualisation and Analysis in SSC-Stat (Data, Graphics and Statistics in Stata)

Other aspects of Instat See details of the previous slide

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Practical work Instat should have been installed for you It comes with a tutorial And there is an extensive demonstration

The first practical gives 2 options The tutorial for those who are more experienced The demonstration for those with less experience What you choose is up to you – and your staff!

And then asks for your initial views Two things you liked Two things you did not like

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Discussion Evaluate Instat

In its own right And as an example of a statistics package Also the demonstration exercise

Consider Ease of use Potential for further work Advantages and limitations

compared to a spreadsheet

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Initial views on Instat

What were your likes? What were your dislikes?

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Why were statistics packages scary?

Instinctive Statistics is scary, so statistics packages must be scary too!

They used to be All different - and users not experienced in computers Command driven

So you had to learn a language Then you were tied to one package

Data was difficult to transfer between packages Now

All packages are in Windows, so easy to use Data easy to move between packages All similar, so easy to use any, once one is familiar Can be used in addition to Excel

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Objectives: Can you now: Recognise all software has limitations

even Excel!!

Explain the reasons for adding a statistics package

at this stage in the training

See how easy a statistics package is to use hence have confidence that you could easily use another statistics package later, if needed