Question

1. There is a lot of concern among students as to the consistency of marking between lecturers. It is pretty common that lecturers obtain reputations for being “hard markers” or “light markers” but there is often very little to substantiate these reputations. So, a group of students investigated the consistency of marking by submitting the same essay to four different lecturers. The mark given by each lecturer was recorded for each of the 8 essays. It was important that the same essays were used for all lecturers because this eliminated any individual differences in the standard of work that each lecturer was marking. The results are as following:      

Essay	Dr. A	Dr. B	Dr. C	Dr. D
1	62	58	63	64
2	63	60	68	65
3	65	61	72	69
4	68	64	58	62
5	69	65	54	59
6	71	67	63	50
7	78	64	67	50
8	76	73	75	45
Mean	69	64	65	58
St. Deviation	5.8	4.7	7.0	8.6

1. Calculate F statistic (make sure to fill in the table).

Source	SS	Df	Mean square	F
Between groups
Residual

2. What is the effect size?

c) If F obtained is significant use Tukey’s HSD (at an alpha of .05) to locate the significant differences. Please make sure to identify clearly which comparisons differ significantly.

Mean differences	Critical Value

Please write out the appropriate conclusion for your results (alpha level is set at .05; make sure the conclusion is APA).

Answer 1

Part A:

The output is given below:

Part B:

Here, Critical Value is: 4.68

Analysis:

If the calculated mean difference is bigger than the critical value from the critical value table, this means that the two means are significantly different and on the other hand, if it is smaller then the means are same..

End of the Solution..