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*More than 2 dependent samples* A cognitive psychologist was interested in the a

ID: 2906822 • Letter: #

Question

*More than 2 dependent samples*

A cognitive psychologist was interested in the ability to solve puzzles. He selected 24 college sophomores and matched them on the basis of IQ and assigned, in groups of four, to one of four puzzle conditions (six blocks of four). He wants to make sure that all the puzzles are equally difficult. The dependent variable was the amount of time it took for a subject to complete the puzzle. The data are presented below. Were there differences in puzzle difficulty at the .05 level?

Puzzle

Block

1

2

3

4

1

23

34

31

40

2

25

38

36

37

3

27

33

30

32

4

28

32

41

38

5

25

36

39

46

6

22

34

40

39

Puzzle

Block

1

2

3

4

1

23

34

31

40

2

25

38

36

37

3

27

33

30

32

4

28

32

41

38

5

25

36

39

46

6

22

34

40

39

Explanation / Answer

Null Hypothesis: The mean time of all four puzzle are same

Alternative Hypothesis: At least one has significant mean time.


Two-way ANOVA: Time_1 versus Block, Puzzle

S = 3.419 R-Sq = 80.64% R-Sq(adj) = 70.32%

Conclusion: The estimated p-value of the puzzle treatment is 0.000 and less than 0.05 level of significance. Hence, we reject the null hypothesis and conclude that there are differences in puzzle difficulty at the .05 level of significance.

Source DF SS MS F P Block 5 88.333 17.667 1.51 0.245 Puzzle 3 642.167 214.056 18.31 0.000 Error 15 175.333 11.689 Total 23 905.833