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	5	7
13	2	2
10	10	5
7	5	5
8	8	4
10	6	1

(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.

Which of the comparisons had significant differences? (Select all that apply.)

A.) The null hypothesis of no difference should be retained because none of the pairwise comparisons demonstrate a significant difference.

B.) Recall following no delay was significantly different from recall following a half second delay.

C.) Recall following a half second delay was significantly different from recall following a one second delay.

D.) Recall following no delay was significantly different from recall following a one second delay.

Answer 1

Solution:

its anova one way

Null hypothesis:Allthe group means are equal

Alternative Hypothesis:atleast one of the group means are different

Install analysis toolpak in excel and then go to

data>dataanalysis>Anova:singlefactor

you will get

Anova: Single Factor
SUMMARY
Groups	Count	Sum	Average	Variance
Delay	7	54	7.714286	16.90476
Before	7	36.5	5.214286	10.65476
Recall	7	25	3.571429	5.285714
ANOVA
Source of Variation	SS	df	MS	F	P-value
Between Groups	60.92857	2	30.46	2.78	0.088519
Within Groups	197.0714	18	10.95
Total	258	20

Intrepretation:

F(2,18)=2.78

p=0.0885

Statistical Decision:

p=0.0885

p>0.05

Do not reject null hypothesis.

Accept Null hypothesis.

Conclusion:

There is sufficient evidence at 5% level of signficnce to conclude that all the three group means are equal.

(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___3.61____ for each pairwise comparison.

for alpha=0.05

k=3 v=19

Q critical=3.61

Which of the comparisons had significant differences? (Select all that apply.)

Treatments pair	Tukey HSD Qstatistic	Tukey HSD p value	Tukey HSD Inference
Delay vs Before	1.999	0.355805	Insignifcant
Delay vs Recall	3.3126	0.075148	Insignifcant
Before vs Recall	1.3136	0.62346	Insignifcant

mark only option A

A.) The null hypothesis of no difference should be retained because none of the pairwise comparisons demonstrate a significant difference.