In: Statistics and Probability
In a hospital the doctor wish to decide to hire staff. He knows that he needs to have more ward-boys every weekend on other days, but he is trying to find if the need them constant across the rest of the week. He collects data for the number of counters needed day for two months. Use α= 5%. Here are the data: (Hint: ANNOVA TEST)
Mondays:
296, 243,
318, 276,
297, 329,
332, 285, 331
Tuesdays: 263,
299, 321,
305, 294,
263, 248,
318, 275
Wednesdays: 308, 312,
330, 287,
263, 313,
275, 293 295
Thursdays: 274,
299, 261, 247,
298, 296, 276,
282
Answers should be in Word Version Format
Monday | Tuesday | Wednesday | Thursday | Total | |
Sum | 2707 | 2586 | 2676 | 2233 | 10202 |
Count | 9 | 9 | 9 | 8 | 35 |
Mean, sum/n | 300.7778 | 287.3333 | 297.3333 | 279.125 | |
Sum of square, Ʃ(xᵢ-x̅)² | 7219.556 | 5450 | 3450 | 2440.875 |
Null and Alternative Hypothesis:
Ho: µ1 = µ2 = µ3 = µ4
H1: At least one mean is different
Number of treatment, k = 4
Total sample Size, N = 35
df(between) = k-1 = 3
df(within) = k(n-1) = 31
df(total) = N-1 = 34
SS(between) = (Sum1)²/n1 + (Sum2)²/n2 + (Sum3)²/n3 + (Sum4)²/n4 - (Grand Sum)²/ N = 2462.312
SS(within) = SS1 + SS2 + SS3 + SS4 = 18560.43
SS(total) = SS(between) + SS(within) = 21022.74
MS(between) = SS(between)/df(between) = 820.7708
MS(within) = SS(within)/df(within) = 598.7236
F = MS(between)/MS(within) = 1.3709
p-value = F.DIST.RT(1.3709, 3, 31) = 0.2699
Critical value Fc = F.INV.RT(0.05, 3, 31) = 2.9113
Decision:
Do not reject the null hypothesis
ANOVA | |||||
Source of Variation | SS | df | MS | F | P-value |
Between Groups | 2462.3123 | 3 | 820.7708 | 1.3709 | 0.2699 |
Within Groups | 18560.4306 | 31 | 598.7236 | ||
Total | 21022.7429 | 34 |