A researcher wants to determine the impact of soil type on the growth of a certa
ID: 3225821 • Letter: A
Question
A researcher wants to determine the impact of soil type on the growth of a certain type of plant. She grows three plants in each of four different types of soil and measures the growth in inches for each plant after one month resulting in the data below.
Use this data: Assignment 9q2 data FOR R
a) What null hypothesis is the researcher testing if she runs an ANOVA with this data?
One type of soil has a higher mean growth for the plant than the others.
The mean growth of the plant is different in each type of soil.
The variability in growth of the plant in each type of soil is the same.
The mean growth of the plant in each type of soil is the same.
Soil 3 provides a lower mean growth for the plant than the other types of soil.
b) What is the SStrt for the ANOVA? Give your answer to at least three decimal places.
c) What is DFerr for the ANOVA?
d) What is the value of the F statistic for the ANOVA? Give your answer to at least three decimal places.
e) Using a 0.1 level of significance, what conclusion should the researcher reach?
Soil 3 has a lower mean growth for the plant than the other types of soil.
The mean growth of the plant is not the same for all soil types.
There is not enough evidence to reject the claim that the mean growth of the plant is the same in each type of soil.
Soil 1 has a higher mean growth for the plant than the other types of soil.
Explanation / Answer
a) The mean growth of the plant in each type of soil is the same.
b)SStrt for the ANOVA =27.1567
c) DFerr for the ANOVA =8
d)value of the F statistic for the ANOVA =7.006
e)as p vlaue is lower then 0.1 level; we rejec t null hypothesis
The mean growth of the plant is not the same for all soil types.
Groups Count Sum Average Variance soil1 3 34.5 11.5 0.13 soil2 3 37.4 12.46667 0.023333333 soil3 3 27.9 9.3 0.91 soil4 3 37.2 12.4 2.68 ANOVA Source of Variation SS df MS F P-value Between Groups 19.67 3 6.5567 7.0062 0.0125 Within Groups 7.4867 8 0.9358 Total 27.15667 11Related Questions
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