Question

An experiment was conducted to determine whether either firing temperature or furnace position affects the baked density of a carbon anode. The data are as follows:

	Firing Temperature
Position	800 (⁰C)	825 (⁰C)	850 (⁰C)
1	570	1063	565
1	565	1080	510
1	583	1043	590
2	528	988	526
2	547	1026	538
2	521	1004	532

Using Fisher’s LSD method, investigate the differences between the mean baked anode density at the three different levels of temperature, which statement is correct?

• A.

  There is no significant difference between the firing temperatures 800⁰C and 850⁰C

• B.

  There is no significant difference between the firing temperatures 825⁰C and 800⁰C

• C.

  There is no significant difference between the firing temperatures 825⁰C and 850⁰C.

• D.

  There is a significant difference between the firing temperatures 800⁰C and 850⁰C

Answer 1

Applying  Fisher’s LSD method :

critical value of t with 0.05 level and N-k=15 degree of freedom=				tN-k=	2.131
Fisher's (LSD) for group i and j =(tN-k)*(sp*√(1/ni+1/nj)   =					36.70

Difference	Absolute Value	Conclusion
x1-x2	481.67	significant difference
x3-x1	8.83	not significant difference
x3-x2	490.50	significant difference

option A is correct

There is no significant difference between the firing temperatures 800⁰C and 850⁰C