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Statistics: sampling ages of moviegoers

The file HP.xls contains the ages of 48 moviegoers to a recent showing of a Harry Potter movie.The following two methods illustrate in different ways how you might select a random sample of eight moviegoers' ages. In each case use the initial order of the files ages as the starting point, so that the first person in the list is 32 years old and the 48th person is 21.

a. Start in row 18 of Table E.1., and reading across, use the table to pick the sample of eight ages. So if your random number was '48' the age would be '21'. Pick your sample without replacement.

b. In this part you are to use Excel to generate random numbers. Picking eight out of 48 is pretty trivial, but imagine picking 1,200 out of 50,000. You are to use the RANDBETWEEN function.

i) Start again with a worksheet that has the original 48 moviegoers in the original
starting order of the file and label that worksheet tab 'Original'.

ii) Next, open up a new worksheet tab and use the RANDBETWEEN function to pick 48 values from 1 to 400 in Column A. Label this worksheet tab 'Random'.

iii) Now be careful. You are to select those 48 random values and, in Column C, choose the Paste Special option and choose the Values option and then paste. The original column of random numbers should be different now! Finally copy the random numbers from column C back to column C of the Original worksheet.

What is gained from all this? Say you wanted to select a sample of eight as in (a). You could now sort on your random numbers and pick, say, the lowest eight.

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The file HP.xls contains the ages of 48 moviegoers to a recent showing of a Harry Potter movie.The following two methods illustrate in different ways how you might select a random sample of eight moviegoers' ages. In each case use the initial order of the files ages as the starting point, so that the first person in the list is 32 years old and the 48th person is 21.
a. Start in row 18 of Table E.1., and reading across, use the table to pick the sample of eight ages. So if your random number was 48 the age would be 21. Pick your sample without replacement.

Note: there are several methods of using a random number table. I'm using the method here:http://www.evaluationwiki.org/index.php/How_to_Use_a_Random_Number_Table. I'm looking at the last two digits of each group of number and I'm choosing the ones that are between 1 and ...

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