In: Statistics and Probability
Refer to the accompanying data table, which shows the amounts of nicotine (mg per cigarette) in king-size cigarettes, 100-mm menthol cigarettes, and 100-mm nonmenthol cigarettes. The king-size cigarettes are nonfiltered, while the 100-mm menthol cigarettes and the 100-mm nonmenthol cigarettes are filtered. Use a 0.05 significance level to test the claim that the three categories of cigarettes yield the same mean amount of nicotine. Given that only the king-size cigarettes are not filtered, do the filters appear to make a difference?
King Size Nicotine (mg) | 100 mm Menthol Nicotine (mg) | 100 mm Non Menthol Nicotine (mg) | |
1 |
1.1 |
1.1 | .8 |
2 | 1.0 | .9 | 1.2 |
3 | 1.0 | 1.2 | .4 |
4 | 1.1 | .8 | 1.2 |
5 | 1.4 | 1.3 | 1.0 |
6 | 1.2 | 1.4 | .8 |
7 | 1.1 | 1.0 | 1.1 |
8 | 1.0 | 1.2 | 1.2 |
9 | 1.2 | .8 | .9 |
10 | 1.2 | .9 | .9 |
A. Determine the null and alternative hypotheses.
B. Find F test statistic
C. Find P value using F test statistic
D. What is the conclusion for this hypothesis test?
E. Do the filters appear to make a difference?
(A) The Hypothesis:
H0: There is no difference between the mean nicotine content of the 3 types of cigarettes.
Ha: The mean nicotine content of at least one cigarette is different from the others.
________________________________________________
(B) The ANOVA Table is below
Source | SS | DF | Mean Square | F |
Between | 0.17 | 2 | 0.08 | 2.01 |
Within/Error | 1.11 | 27 | 0.041 | |
Total | 1.28 | 29 |
Calculations For the ANOVA Table:
Overall Mean : Since n is equal , the overall mean = mean of means
= (1.13 + 1.06 + 0.95) / 3 = 1.05
SS treatment = SUM [n* ( Individual Mean - overall mean)2] = 10 * (1.13 - 1.05)2 + 10 * (1.13 1.05)2 + 10 * (1.13 - 1.05)2 = 0.17
df1 = k - 1 = 3 - 1 = 2
MSTR = SS treatment / df1 = 0.17 / 2 = 0.08
SS error = SUM (Sum of Squares) = 0.14 + 0.4 + 0.57 = 1.11
df2 = N - k = 30 - 3 = 27
Therefore MS error = SS error / df2 = 1.11 / 27 = 0.041
F = MSTR / MSE = 0.08 / 0.041 = 2.01
______________________________________________
(C) The p value is calculated for F = 2.01 for df1 = 2 and df2 = 27
p value = 0.1541
_____________________________________________
(D) Since p value is > , We fail to reject H0.
The Conclusion: There isn't sufficient evidence at the 95% level of significance to conclude that the
mean nicotine content of at least one cigarette is different from the others.
________________________________________________
(E) No, since the null hypothesis that the mean nicotine content of at least one cigarette is different from the others has been failed to be rejected, we dont have sufficient evidence that the filters are effective.
________________________________________________