StatCrunch: Computing Summary Statistics for Columns
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StatCrunch: Computing Summary Statistics for Columns

In this video, you will learn
to create summary statistics for a column of data
using StatCrunch. The data set I will be
using is called exam scores. This data set
contains one column of data of 23 exam scores from
an introductory statistics course. Let’s compute the
summary statistics for the exam 2 column. To do so, under the stat
menu choose summary stats by columns. I’m going to select the exam
2 column and click compute. By default, StatCrunch
produces a table with 11 summary statistics
for the exam 2 column. However, StatCrunch
also allows the user to customize the statistics that
are displayed in this table. To do so, back under the
options menu, choose edit. This takes us back to
the original window where we built our table. In this window, StatCrunch
has other options for the user to customize their table. Under the statistics box, you
will see the different options that the user can
add to their table. To select or deselect
any of these options, hold down command on a
Mac, or control on a PC. For this example, I’m
going to add n, mean, and standard deviation
only to our table. Click compute, and
now our table only displays those three
summary statistics. StatCrunch also allows the user
to add percentile statistics to their table. To do so, back under
options– edit. In the percentile box, you
can enter different values. For this example,
I’d like to see the value of the 10th
and the 90th percentiles. So I will enter 10 separated by
a comma, and then type the 90. When I click compute
it has now entered the 10th and the 90th
percentiles to our table. Lastly, StatCrunch
also allows the user to create their own
custom statistic. Back under options
again, there’s a box labeled other statistics. In this box you can type a wide
array of StatCrunch functions to be applied to
the column of data. The column is going
to be labeled as an x. To see the different functions
that StatCrunch can use, click the blue build button. Here on the right hand side
is the list of the StatCrunch functions that can be used. For this example, I know which
function I’d like to use. So I’m going to type in
the standard deviation, and this is for the x column,
times the standard deviation of the x column as well. This is equivalent
to variance, so I’m going to go on ahead and add
variance back into our table to verify the equivalence
of the custom statistic I have created. I’ll click compute and the
variance is approximately 92.7, and my new custom statistic I
created is equivalent of 92.7.

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