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Psyc 110 |
Lab 3
Descriptive & Inferential Statistics |
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Dr. R. G. Tonks |
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For this activity you will be asked to collect some data, develop some basic summary statistics, and you will perform a t-test for significance the data. You will also be asked to report on what conclusions may be drawn from this sample about the general population.
Instructions:
The variables at hand are gender and the number of hats that people own. You are expected to go out into the world and collect responses from 10 males and 10 females (you can be one of the people yourself). Do not use any identifying information (names), only record the information in the format below:
Gender |
Number |
M |
12 |
F |
6 |
M |
10 |
After you have collected your data follow the information on this link and go to Vassar Stats and complete a t-test of the data.
What is the independent variable ? What is the dependent variable?
What is your Mean, Median, Mode, and Range
Part 2: Inferential
Statistics
In this second part you will make an hypothesis about gender and its relationship to number of hats, and then calculate the t-statistic that will tell you whether or not there
exists some relationship between these variables.
Now that you have your data you can enter the numbers into Vassar Stats program for computing a t-test.
T-tests, as you might recall
are done when there are only two groups being compared (i.e., males &
females), while ANOVA is done for more than two groups.
How to
calculate the t-test in Vassar Stats.
i) Click on the link above to 'VassarStats'
ii) Select 't-test & procedures' from the left hand column
iii) Select 't-test for Independent Samples [cell-entry format]' (We use
Independent Samples because the participants in our two groups are different … a
between-subjects design)
iv) A small prompt window will appear. Enter in your numerical value for n (how
many participants in the largest group)
** If you are having troubles getting the prompt window, disable your pop-up
blocker or click allow pop-ups.
v) Enter in your data for males and females.
vi) Click the calculate button.
After you have
done the analysis, your lab report should include:
The
answers to questions from Part I
thus the means and standard deviations for the two groups, and the t
statistic and the p value that you calculated using Vassar stats.
For your report also consider what answers to
the following questions you might come up with:
What Conclusions can you draw from this study?
[note:] Most of genetic and evolutionary psychology operates much this way, making use of general categories of people (by gender, "race", region or what ever and then looking at certain traits or attributes (like number of hats, or partners, or interest in machines or dialogue, body weight, personality, intelligence, ....etc.).
Typically they make hypotheses about such "genetic" and /
or "environmental" variables to try to determine their relationships
through correlations or such tests of group differences (t-test, ANOVA).
In the end you are left with a probability number that tells you whether or not
the observed difference is likely to be real, rather than by random chance. It
does not tell you that your hypothesis is true, but it can tell you that it is
likely to be false or not.
Keeping this in mind. .... what are your
conclusions?
What type of follow up study might you do? Why ?