PSY 232 Stats/Methods II
Assignment 3-Computing t-tests in SPSS (cont.)
Points: 10

This assignment requires students to use SPSS to compute the appropriate t-statistic. For each problem, run the t-test in SPSS and hand write the following additional information on the printout: (1) State the null and alternative hypotheses; (2) Write the test statistic (no special format required here) and indicate your decision (retain Ho or reject Ho); and (3) Write a couple of sentences showing how the results would be reported in the Results section of an APA paper (See G&W pages 296, 323-324, and 349-350 for "In the Literature" APA samples).

Each printout must have your name and lab day typed at the top. Please staple.

• Scenario E: 
  Starting in August of 2006, a program to decrease littering was implemented in four cities in California. The amount of litter in the streets (average pounds of litter collected per block per day) was measured during the July before the program started and then the next July, after the program had been in effect for a year. The results are as follows:

               Fresno           Merced        Bakersfield        Stockton

July '06        9                       10                   8                      9

July '07        2                        4                    9                      1

• Scenario F
  The amount of oxygen consumption was measured in six individuals over two 10-minute periods while sitting with their eyes closed. During one period, they listened to an exciting adventure story; during the other, they heard restful music.
  Participant    Story    Music
  1                    6.12    5.39
  2                    7.25    6.72
  3                    5.70    5.42
  4                    6.40    6.16
  5                    5.82    5.96
  6                    6.24    6.08
  Based on these results, is oxygen consumption less when listening to the restful music? Use the .05 level of significance.

• Scenario G
  A researcher is comparing the effectiveness of two sets of instructions for assembling a child's bike. A sample of eight fathers is obtained. Half of the fathers are given one set of instructions and the other half receives ;;the second set. The researcher measures how much time is needed for each father to assemble the bike. The scores are the number of minutes needed by each participant.
  Instruction Set 1    Instruction Set 2
  8                            14
  4                            10
  8                              6
  4                            10
  
• Scenario H
  Pelton (1983) reported that Olympic-level marksmen shoot much better if they fire between heartbeats rather than squeezing the trigger during a heartbeat. The small vibration caused by a heartbeat seems to be sufficient to affect the marksmen's aim. A sample of n = 8 Olympic marksmen fire a series of rounds while a researcher records heartbeats. For each marksman, the total score is recorded for shots fired during heartbeats and shots fired between heartbeats. Do these data indicate a significant difference? Test with alpha = .05.
  Participant    During    Between
  A                    93            98
  B                    90            94
  C                    95            96
  D                    92            91
  E                    95            97
  F                    91            97
  G                    92            95
  H                    93            97