In: Statistics and Probability
Do lizards play a role in spreading plant seeds? Some research carried out in South Africa would suggest so. Researchers on a study collected 400 seeds of a particular type of fig, 100 of which were from each treatment: lizard dung, bird dung, rock hyrax dung, and uneaten figs. They planted these seeds in batches of 5, and for each group of 5 they recorded how many of the seeds germinated. This resulted in 20 observations for each treatment. The treatment means and standard deviations are given in the accompanying table.
Treatment | n |
x |
s |
---|---|---|---|
Uneaten figs | 20 | 2.40 | 0.30 |
Lizard dung | 20 | 2.30 | 0.33 |
Bird dung | 20 | 1.70 | 0.35 |
Hyrax dung | 20 | 1.45 | 0.27 |
(a)
Construct the appropriate ANOVA table. (Use technology. Round your answers to three decimal places.)
Source of variation |
Degrees of freedom |
Sum
of squares |
Mean squares |
F Ratio | F Prob |
---|---|---|---|---|---|
Between Groups | |||||
Within Group | |||||
Total | 79 |
Test the hypothesis that there is no difference between mean number of seeds germinating for the four treatments. (Use a significance level of 0.05.)
State the appropriate null and alternative hypotheses. (Let μ1, μ2, μ3, and μ4 be the true means for the four different treatments.)
H0 : μ1 =
μ2 = μ3 =
μ4
Ha : at least three of the four
μi's are differentH0 : at
least two of the four μi's are different
Ha : μ1 =
μ2 = μ3 =
μ4 H0
: μ1 = μ2 =
μ3 = μ4
Ha : at least two of the four
μi's are differentH0 :
μ1 = μ2 =
μ3 = μ4
Ha : all four of the
μi's are differentH0 : all
four of the μi's are different
Ha : μ1 =
μ2 = μ3 =
μ4
State the test statistic and P-value. (Use technology. Round your answers to three decimal places.)
F=
P-value=
State the conclusion in the problem context.
We reject H0. The data do not provide convincing evidence that the mean number of seeds germinating for the four populations is not the same.We fail to reject H0. The data do not provide convincing evidence that the mean number of seeds germinating for the four populations is not the same. We fail to reject H0. The data provide convincing evidence that the mean number of seeds germinating for the four populations is not the same.We reject H0. The data provide convincing evidence that the mean number of seeds germinating for the four populations is not the same.
(b)
Is there evidence that seeds eaten and then excreted by lizards germinate at a higher rate than those eaten and then excreted by birds? Give statistical evidence to support your answer. (Use a table. Use μlizard − μbird. Round your answers to three decimal places.)
Assume the value of q is 3.72. There ---is, is not--- is not is evidence that seeds eaten and then excreted by lizards germinate at a higher rate than those eaten and then excreted by birds. The 95% T-K confidence interval is (____,_____) which ---does, does not--- does does not contain zero. This ---indicates, does not indicate--- indicates does not indicate a significant difference between the germination rate between those two population.