AP Psychology

Statistics: t-tests

Name: ____________________________

No trick questions this time, I promise!

I. Remember Maxine and her study on smoking and anxiety? Well, Maxine finally realized that correlating nominal data requires a special statistical technique that she is not familiar with. Therefore, she has decided to COMPARE the anxiety levels of the male and female subjects in order to determine if a statistical difference exists. The following table contains her data.

MALES

FEMALES

10

12

28

17

7

16

15

36

16

15

20

17

10

21

18

26

15

14

21

12

8

20

24

15

10

20

20

8

12

7
  1. Calculate and report the means and standard deviations for the male subjects and the female subjects with respect to their levels of anxiety.

    2.  

     

  2. Conduct a t-test and report the value of "t" and the value of "p".

    3.  

     

  3. What can you conclude from this test?

    4.  

     

  4. Since random assignment was not (and could not) be utilized in this study and since no variable was manipulated, how would you classify this type of research IN GENERAL?

    5. a) Non-experimental                             b) Experimental

  5. How would you classify it SPECIFICALLY?

a) Correlational        b) Differential        c) Quasi-experimental        d) True experiment

 

II.    Vito wants to determine whether subjects exhibit greater recall for active-declarative sentences (ex: Joe rang the doorbell) than for passive-negative sentences (ex: The doorbell was not rung by Joe). Vito obtained 30 subjects and assigned them at random to two groups of 15 subjects each. One group (group A) is read 25 active-declarative sentences, with a recall test after each sentence. The other group (group B) hears and recalls passive-negative forms of the sentences used for group A. The number of sentences correctly recalled by each subject are presented in the following table.

GROUP A

GROUP B

17

17

21

18

22

18

16

15

18

20

21

16

15

16

20

13

18

17

13

14

13

18

19

16

14

13

15

14

16

15

 

  1. Calculate and report the means and standard deviations for both groups

    2.  

     

  2. Conduct a t-test and report the value of "t" and the value of "p".

    3.  

     

  3. Since random assignment was used in this study and since a variable was manipulated, how would you classify this type of research IN GENERAL?

    4. a) Non-experimental b) Experimental

  4. How would you classify it SPECIFICALLY?

    5. a) Correlational b) Differential c) Quasi-experimental d) True experiment

  5. What was the independent variable?
  6. What was the dependent variable?
  7. What can you conclude from the statistical test?

    8.  

     

    III. Mr. Sprocket, the principal of a private elementary school wants to determine if phonics is superior to "whole word" reading. Ms. Perry, the 2nd grade reading teacher takes two intensive courses in both reading techniques over the summer break. Beginning in September, she uses phonics in her morning reading classes and whole-word reading in her afternoon classes. At the end of the school year, all students are given a standardized reading achievement test (the RAT). The following table presents the reading scores for the two groups of students.

    PHONICS

    WHOLE-WORD READING

    45

    16

    20

    33

    30

    19

    33

    25

    26

    40

    28

    36

    15

    26

    32

    43

    20

    17

    30

    25

    19

    34

    28

    23

    41

    26

    40

    16

    23

    34

    25

    24

    22

     

  8. Calculate and report the means and standard deviations for both groups

    9.  

     

  9. Conduct a t-test and report the value of "t" and the value of "p".

    10.  

     

  10. Since random assignment was not used in this study, yet a variable was manipulated, how would you classify this type of research IN GENERAL?

    11. a) Non-experimental                 b) Experimental

  11. How would you classify it SPECIFICALLY?

    12. a) Correlational       b) Differential       c) Quasi-experimental       d) True experiment

  12. What was the independent variable?
  13. What was the dependent variable?
  14. What can you conclude from the statistical test?

 

  


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