In: Statistics and Probability
In a completely randomized design, 12 experimental units were used for the first treatment, 15 for the second treatment, and 20 for the third treatment. Complete the following analysis of variance (to 2 decimals, if necessary). Round p-value to four decimal places. If your answer is zero enter "0".
Source of Variation | Sum of Squares | Degrees of Freedom | Mean Square | F | p-value |
Treatments | 1,300 | ||||
Error | |||||
Total | 2,000 |
At a .05 level of significance, is there a significant
difference between the treatments?
The p-value is Selectless than .01between .01 and
.025between .025 and .05between .05 and .10greater than .10Item
9
What is your conclusion?
SelectConclude not all treatment means are equalCannot reject the
assumption all treatment means are equal
Answer:
From given information
The sum of squares for error is
SSE = SST-SSTR
SSE = 2000-1300
SSE = 700
Degree of freedom:
Here
N = 12+15+20
N = 47
df(treatment) = k-1
df(treatment) = 3-1
df(treatment) = 2
df(total) = N -1
df(total) = 47-1
df(total) = 46
df(error) = N - K
df(error) = 47-3
df(error) = 44
Now to find the mean square error:
MSE = SSE /N-k
MSE = 700/ 47-3
MSE = 700/ 44
MSE = 15.909
Therefore the mean squrae error is 15.909
Now to find the mean square treatment:
MSTR = SSTR/(k-1)
MSTR = 1300/(3-1)
MSTR = 1300/2
MSTR = 650
Therefore the mean square treatment is 650
Now to find the F- statistic:
F- statistic = MSTR / MSE
F- statistic = 650/ 15.909
F- statistic = 40.8574
Therefore the value of F- statistic is 40.8574
Now to find the P- Value:
P- value = 0.0000
Source of Variations | Sum of Squares | Degrees of freedom | Mean square | F | P- Value |
Treatment | 1300 | 2 | 650 | 40.8574 | 0.0000 |
Error | 700 | 44 | 15.909 | ||
Total | 2000 | 46 |
The P- Value is less than 0.01
Decision:
P -Value <
0.0000 < 0.05
Since the P -Value is less than significance level.Therefore we reject the null hypothesis(H0) at 0.05 level of significance.
Conclusion:
Conclude not all treatment means are equal.