Programming Assignment 2

CSC 323 - Data Analysis and Statistical Software

Due: 8/23/2001

 

You have been assigned to a software development team that is conducting a series of usability tests on a new version of a browser based user interface. The interface has been designed with expert users in mind and so has features to accommodate such users (see the Novice vs. Expert Users essay from Jakob Nielsens useit.com site).

Your team must demonstrate that the proposed interface will allow expert users to complete tasks more efficiently than the existing interface. You have been asked to assist with a controlled experiment involving twenty expert users. The purpose of this experiment is to determine if the proposed interface allows expert users to complete tasks more quickly than the existing interface. Two standard tasks (Task #1 and Task #2 below) have been defined for the experiment. For the existing interface, it is known that the mean time to complete task #1 is 50 seconds and the mean time to complete task#2 is 90 seconds.
Note: See the Usability Metrics essay for additional details on usability as well as details of a controlled experiment conducted by Macromedia.

You have been presented with the data collected for this experiment. Each observation in the file consists of the following values:

Conduct a thorough analysis of these data. You will need to conduct a test of hypotheses for each task. You must also submit a report summarizing your findings. See additional details below.

  1. Write a SAS program to analyze this dataset. Your program should do the following:
    1. Read your data from an external file.
    2. Execute the PRINT procedure.
    3. Use the appropriate SAS procedures to produce the statistics and p-values to test your hypotheses.

    Note: For PROC PRINT, be sure to use labels for column headings rather than variable names. Use names for data sets and variables that are meaningful. You should generate an appropriate title for the output of these procedures.

  2. Write a short analysis (no more than two pages) of the output of your SAS program. Your analysis should at least address the following:
    1. State your primary hypotheses. That is, NULL and ALTERNATIVE hypotheses for the experiment described above.
    2. State and address other hypotheses needed for your analysis.
    3. Discuss the significance of the p-value obtained for each of the primary hypotheses.
    4. For each primary primary hypotheses, briefly comment on why you should (or should not) provide a point estimate for the parameter in question. If you argue that a point estimate for the parameter is appropriate then you must provide it as well as a 95% confidence interval (with interpretation).