In: Statistics and Probability
A new operator was recently assigned to a crew of workers who perform a certain job. From the records of the number of units of work completed by each worker each day last month, a sample of size five was randomly selected for each of the two experienced workers and the new worker. At the α = .05 level of significance, does the evidence provide sufficient reason to reject the claim that there is no difference in the amount of work done by the three workers?
Workers | |||
New | A | B | |
Units of work (replicates) | 9 | 11 | 13 |
8 | 10 | 11 | |
10 | 13 | 9 | |
8 | 13 | 11 | |
10 | 13 | 12 |
(a) Find the test statistic. (Give your answer correct to two
decimal places.)
(ii) Find the p-value. (Give your answer bounds
exactly.)
_____< p < ____
An experiment was designed to compare the lengths of time that four different drugs provided pain relief after surgery. The results (in hours) follow. Is there enough evidence to reject the null hypothesis that there is no significant difference in the length of pain relief provided by the four drugs at α = .05?
Drug | |||
A | B | C | D |
4 | 5 | 7 | 2 |
5 | 5 | 8 | 2 |
3 | 6 | 12 | 4 |
4 | 5 | 9 | |
10 |
(a) Find the test statistic. (Give your answer correct to two
decimal places.)
(ii) Find the p-value. (Give your answer bounds
exactly.)
____< p < ____
Ans a ) using excel>data>data analysis >one way ANOVA
we have
Anova: Single Factor | ||||||
SUMMARY | ||||||
Groups | Count | Sum | Average | Variance | ||
New | 5 | 45 | 9 | 1 | ||
A | 5 | 60 | 12 | 2 | ||
B | 5 | 56 | 11.2 | 2.2 | ||
ANOVA | ||||||
Source of Variation | SS | df | MS | F | P-value | F crit |
Between Groups | 24.13333 | 2 | 12.06667 | 6.961538 | 0.009839 | 3.885294 |
Within Groups | 20.8 | 12 | 1.733333 | |||
Total | 44.93333 | 14 |
(a) the test statistic F = 6.96
(ii)the p-value
0.005<p <0.01
Ans 2 )
using excel>data>data analysis >one way ANOVA
we have
Anova: Single Factor | ||||||
SUMMARY | ||||||
Groups | Count | Sum | Average | Variance | ||
A | 4 | 16 | 4 | 0.666667 | ||
B | 4 | 21 | 5.25 | 0.25 | ||
C | 5 | 46 | 9.2 | 3.7 | ||
D | 3 | 8 | 2.666667 | 1.333333 | ||
ANOVA | ||||||
Source of Variation | SS | df | MS | F | P-value | F crit |
Between Groups | 101.2208 | 3 | 33.74028 | 20.02721 | 5.78E-05 | 3.490295 |
Within Groups | 20.21667 | 12 | 1.684722 | |||
Total | 121.4375 | 15 |
(a) the test statistic F = 20.03
(ii)the p-value
0.<p <0.00001