Basic Statistics/Statistics for Everyday Life
Introduction
StatCrunch is an online program for statistical analysis. It offers many advanced
statistical features but is geared towards a student audience.
Once you open StatCrunch, you should see a Session area like the one below. The
variable names of the data are entered in column var1, var2, var3, etc. Let’s enter some
data for 2 different variables. The first variable is, “Test Grade” and the other variable
“Gender”. Right now our Worksheet should look something like the following:
The actual data will be put in the white cells below “Test Grade” and “Gender”. Under “Test
Grade” enter the values: 85, 78, 76, 46, 51. Under “Gender” enter: m, m, f, f, f so that your
screen will look like the following:
What this suggests is that we
surveyed/sampled 5 people and
we had them tell us what their test
grade was and what their gender
was. Person #1 answered: 85 and
male, Person #2 answered: 78 &
male and so on.
Let’s enter more data for Test Grade and Gender.
After you enter the data on the left, let’s see some of the
things that StatCrunch can do. Unfortunately, most if not
all the information will seem foreign to you. However, this
is to show you the various paths so that when you do need
this information, you will have an idea what to do.
1. Let’s get some descriptive statistics. Use the following
path:
(Stat > Summary Stats > Columns). In the box under
Select columns, click on the variable “Test Grade” hit the
“Next” button and click “Calculate”. In the Statistics box
the various statistics in blue are automatically selected, we
can either add some of those in the white area or deselect
some of those in the blue area depending on our research
interest. However, we will concentrate on does in the blue
box. All of these figures will be discussed later in the
semester.
2. Let’s make some graphs for quantitative data:
Histogram: (Graphics < Histogram < Click Test Grade<
Create Graph)
Dot Plot: (Graphics < Dot Plot < Click Test Grade< Create
Graph)
Stem and Leaf: (Graphics < Stem and Leaf < Click Test
Grade< Create Graph
Box Plot: (Graphics < Box Plot <click Test Grade < Click Next < check both “use fences to
identify outliers” and “Draw boxes horizontally” < Click create Graph)
Now some information regarding qualitative data:
(Graphics < Bar plot < With Data< Click Gender< Click Next < Check in “Display values above
bars if possible”
(Stat < Tables < Frequency… {Select Gender} < Check in “Percent of Total” < Calculate
4. For the quantitative graphs and the display of the descriptive statistics, all of them can be
separated by a qualitative variable, such as gender. Let’s go ahead and do that for some of the
functions we already performed.
Descriptive Statistics by groups: (Stat > Summary Stats > Columns > Enter Test Grade for
Variables and Gender for Group by} < Calculate
Dot Plot by Groups: (Graphics < Dot Plot < Click Test Grade < Select gender for group by box}
< Create Graph. Notice all the same statistics were displayed but for both males and females.
Keep this sheet for reference later in the semester.