Calculate the mean and standard deviation; instructions are given in the Excel document. (If you
would prefer to use SPSS to complete this assessment, use these instructions for analysing the data
in SPSS (AdditionalResources/A1-resource_SPSS-instructions.html).)
Transfer the mean and standard deviation to your table in Excel (for later reference in the online
test).
3. Use a one-sample t-test to calculate the signi⌀⌅cance of your result
If you were not caught out by the illusion, the ideal score would be 0 (no error). You can perform a
one-sample t-test (which compares your results to this ideal). Again, the instructions for performing
the test are given in the Excel document.
Copy and paste outcomes of your calculations and scatterplots into your own notebook for later
reference in the online test. Include t values, degrees of freedom (df), standard error (of the mean),
and probability (p values). (Note that all t-tests should be two-tailed unless you have no interest in
the result if it happens to go in the opposite direction, which is quite rare.) Write a sentence below
reporting these statistics. Begin with 'A one-sample t-test was performed….'. This practice will be
helpful when you need to write up your major lab report.
Task 2: Estimating size of objects (What to take away for the holidays)
1. Estimate the sizes
Have you ever wondered how you decide what to pack into the trailer or in the boot, before you
put everything outside and begin with the ⌀⌅ddling? Haber and Levin (2001) decided to test whether
people had memories of the familiar size of objects.
In the second tab of the Excel spreadsheet (AdditionalResources/PSY20006_Assessment-
1_Spreadsheet.xlsx), you will ⌀⌅nd a list of 30 objects that might be useful on your holidays. From
memory, estimate the length (longest dimension) of each of them in either feet/inches, or
metres/centimeters. As Haber and Levin have their measures in feet and inches, you will need to
convert your estimates to feet to be able to compare them with those in the article. Conversions
are available if you use Google (e.g., search for 'meters to feet').
2. Locate and read Haber and Levin (2001)
You can ⌀⌅nd a reference to Haber and Levin (2001) on page 68 of your eText (Eysenck and Keane,
2015). Use the reference section of your eText to source the original article. (It is free if you go
through the Swinburne Library (http://www.swinburne.edu.au/library/).)
Read the article to complete the test questions. Note that the test focuses on the overall purpose of
the paper, and on Experiment 1 (more than Experiment 2).
3. Compare measured and estimated lengths
Locate Table 1 from Experiment 1 in the article by Haber and Levin (2001). Their table shows the
means and standard deviations for direct measures of common objects and for cognitive estimates
that their participants made.

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