Question

To determine the effect of two glass types and three phosphor types on the light output of a television tube, light output is measured by the current required in series with the tu to produce 30 foot-lamberts of light output. Thus the higher the current, in microamperes the poorer the tube in light output. Three observations were taken under each of the six treatment conditions and the experiment was completely randomized. The following data were recorded Phosphor Type Glass Type 270 285 290 220 225 230 300 310 295 260 240 235 280 290 285 230 235 240 a. Do an ANOVA on these data and test the effect of glass type, phosphor types, and interaction on the current flow

Answer 1

excel steps for Anova

write data in excel>menu>data>data anaysis>two way anova with replication>enter required label>ok,

following o/p is obatined

Anova: Two-Factor With Replication
SUMMARY	A	B	C	Total
1
Count	3	3	3	9
Sum	855	905	845	2605
Average	285	301.6667	281.6667	289.4444
Variance	25	58.33333	108.3333	134.0278
2
Count	3	3	3	9
Sum	705	735	675	2115
Average	235	245	225	235
Variance	25	175	25	131.25
Total
Count	6	6	6
Sum	1560	1640	1520
Average	260	273.3333	253.3333
Variance	770	1056.667	1016.667
ANOVA
Source of Variation	SS	df	MS	F	P-value	F crit
Sample	13338.89	1	13338.89	192.08	9.57E-09	4.747225
Columns	1244.444	2	622.2222	8.96	0.004162	3.885294
Interaction	44.44444	2	22.22222	0.32	0.732158	3.885294
Within	833.3333	12	69.44444
Total	15461.11	17

p-value for glass type= 0.000

p-value <α=0.05, test is significant

hence, there is significant difference in means of glass type at α=0.05

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p-value for phosphorus types = 0.004

pvalue <α=0.05,, test is significant

hence, there is significant difference in means of three phosphorus type at α=0.05

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p value for interaction=0.732

p value >α=0.05, test is not significant

hence, there is no significant interaction between glass and phosphorus type at α=0.05