Putting AUTOGRAPH to work with data  
 

Although Autograph is principally a coordinate geometry package, it does handle data in both single-variable mode and bi-variate. It can also tackle the tricky concepts of discrete and continuous variables, and also frequency and frequency density when the classes are unequal.  
  BABY DATA: USING AUTOGRAPH FOR LINEAR REGRESSION  
 


First load the Baby Data xls file on the previous data page.

It is important always to verify data that is 'off the web' - it could have come from anywhere. Make sure it is reasonable and likely to be useful.

Watch the video to have a tour of the dataset, and see how Excel then Autograph can be used to explore the relationship between the length of gestation and the birth weight of the baby.

 


 
  BABY DATA: USING AUTOGRAPH TO TEST WHICH VARIABLES ARE NORMAL  
 


It is important to get a good feel for which variables in a data set are likely to be normally distributed.

This Baby dataset has many variables to look at. Watch the video to see which are and which are not normal, and think about why.

 

 
  BABY DATA: USING AUTOGRAPH FOR HISTOGRAMS  
 

 

This video takes the set of 1175 ages of Mothers having babies and creates a histogram in Autograph.

It then discusses how Autogrpah copes with the tricky concepts of

(a) discrete and continuous variables

(b) frequency density (particularly when the class intervals are not equal)

You may need to watch this more than once!

 
  WHY DO THEY WEIGH THE LUGGAGE AND NOT US? AN INVESTIGATION USING AUTOGRAPH  
 


I have long wondered why they weigh the luggage, but not the passengers. Surely the pilot must need to know the total weight of the passengers?

First we need some data, and for this go to the TSM useful files page and download the Excel file whcih has data for over 7500 "Weights of Patients".

Watch this video to see how to paste this data into Autograph. See how to use the "sample means" utility to explore the distribution of the sample means of passengers starting with just 5 passengers, then 18 (as in the Charlotte air crash) and finally a typical jumbo jet with 350 on board!

 

 
   
Douglas Butler
 

 

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