STA305s14 Computer Assignment Seven
Quiz in lecture on Monday March 31st

1. A company studied the effects of three different types of promotions on sales of its crackers:
   • Treatment 1: Sampling of product by customers in store and regular shelf space.
   • Treatment 2: Additional shelf space in regular location.
   • Treatment 3: Special display shelves at ends of aisle in addition to regular shelf space.
   Here are the data. Y is sales, and X is sales last period, which will be used as a covariate.

   Promo   Y   X
   1       38 21 
   1       39 26
   1       36 22
   1       45 28
   1       33 19
   2       43 34
   2       38 26
   2       38 29
   2       27 18
   2       34 25
   3       24 23
   3       32 29
   3       31 30
   3       21 16 
   3       28 29
   

   1. Test the assumption of parallel regression lines. If the null hypothesis is not rejected, use a parallel regressin lines model for the rest of the question.
   2. Test the effect of promotion controlling for the covariate.
   3. If promotion has an effect at the α=0.05 level, test for pairwise differences with a Bonferroni correction.
   4. Be ready to state your conclusions in plain, non-statistical language.

    

2. An accounting firm tests three different methods of training its employees: (1) Study at home, (2) training sessions at local offices conducted by local staff, and (3) training sessions at headquarters conducted by national staff. Thirty employees were grouped into 10 blocks of three, according to time elapsed since graduation from university. Block 1 consists of auditors graduated most recently, block 10 consists of those graduated longest ago. Within each block, participants were randomly assigned to training programmes. Learning was assessed by a test score. Here are the data:

   Participant   Block      Method      Score
       1           1           1           73
       2           1           2           81
       3           1           3           92
       4           2           1           76
       5           2           2           78
       6           2           3           89
       7           3           1           75
       8           3           2           76
       9           3           3           87
      10           4           1           74
      11           4           2           77
      12           4           3           90
      13           5           1           76
      14           5           2           71
      15           5           3           88
      16           6           1           73
      17           6           2           75
      18           6           3           86
      19           7           1           68
      20           7           2           72
      21           7           3           88
      22           8           1           64
      23           8           2           74
      24           8           3           82
      25           9           1           65
      26           9           2           73
      27           9           3           81
      28          10           1           62
      29          10           2           69
      30          10           3           78
   

   If training method has an effect at the α=0.05 level, test for pairwise differences with a Bonferroni correction. Be ready to answer all the usual questions (what is the F statistic, the p-value, etc.). Be able to state your conclusions in plain, non-statistical language.

Bring both your log file and your procedure output file to the quiz. You will be asked to hand them in with your quiz. Please put your name and student number in the title statement.

Please be reminded of the rules for computer assignments and quizzes. See the syllabus for more detail.

• You may copy freely from me, but do not look at anyone else's SAS code before the quiz.
• Do not show your SAS code to any other student in the class.
• Do not write anything on the printouts.
• Important: Comment statements and other typed material that would help with interpretation of the computer output are expressly forbidden. For example, you may not type assignment questions or answers into your code, or otherwise cause them to appear on your log file or procedure output file. Any such material is an unauthorized aid for the purposes of this course, and if you use or possess an unauthorized aid, you will be charged with an academic offence.
• The log and procedure output files must be generated at the same time by the same SAS program or you may lose a lot of marks.

The problems in this assignment are borrowed from an old textbook.