Movie PPDAC Inquiry

Sampling Avoiding Bias
There are too many movies here for us to process.  We need to pick a smaller sample so we can easily find the measures of the middle and the spread of the data.  

So how do we pick our sample?  Answer we choose randomly.  Technically random means every part of the population has an equal chance of being picked. 

Here is how to do a random sample.  Give every part of the population a number (the movies are numbers 1 to 100 already). 

Use a random number generator (10 sided dice will do this - first roll is the tens and the second roll for the ones). 

Here is a link to a random number generator online. 

Here is an online ten diced dice roller.  It is showing two dice a two and a three meaning the number 23 (on the movie database for 2013 that's the movie Evil Dead which raised $54 million dollars).


Question - Can we double count?  If the random number 23 came up again should we have Evil Dead appear in our sample twice?  Answer - No we just ignore the repeat.  It catches out students because they often forget to replace the ignored one.

We are aiming to have a big enough sample to be more accurate (too small and it can lead to bad conclusions). 

Recording our Data - It takes a long time to write out the names of the movies.  So instead to show our selection just use a highlighter to help you remember which ones you picked.  That way the only things we have to use in the calculator (or spreadsheet) are the actual numbers.