Question

Iconic memory is a type of memory that holds visual information for about half a second (0.5 seconds). To demonstrate this type of memory, participants were shown three rows of four letters for 50 milliseconds. They were then asked to recall as many letters as possible, with a 0-, 0.5-, or 1.0-second delay before responding. Researchers hypothesized that longer delays would result in poorer recall. The number of letters correctly recalled is given in the table.

Delay Before Recall
0	0.5	1
6	10	4
10	2	4
10	4	2
11	6	6
5	6	2
6	8	6

(a) Complete the F-table. (Round your values for MS and F to two decimal places.)

Source of Variation	SS	df	MS	F
Between groups
Within groups (error)
Total

b) Compute Tukey's HSD post hoc test and interpret the results. (Assume alpha equal to 0.05. Round your answer to two decimal places.)

The critical value is _____ for each pairwise comparison.

Answer 1

a)

Source of variation		SS	df	MS	F
between		37.79	2.00	18.89	1.91
within		178.50	18.00	9.92
total		216.29	20.00

b)

Tukey's (HSD) for group i and j =                  (q/√2)*(sp*√(1/ni+1/nj)         =

4.30