Question
Use the file treesoil.csv that is available below. This dataset contains categorical data on the species of 464 trees (big leaf maple, Douglas fir, red
Use the file treesoil.csv that is available below. This dataset contains categorical data on the species of 464 trees (big leaf maple, Douglas fir, red alder, western hemlock, and western redcedar) and the soil type in which each tree is grown (clay, loam, sand, and silt).
The data below is treesoil.csv:
Tree | Soil |
Douglas fir | clay |
Douglas fir | clay |
red alder | silt |
western hemlock | sand |
western redcedar | clay |
Douglas fir | loam |
western redcedar | loam |
red alder | clay |
big leaf maple | sand |
western hemlock | loam |
western hemlock | loam |
big leaf maple | silt |
Douglas fir | clay |
Douglas fir | clay |
Douglas fir | clay |
Douglas fir | clay |
Douglas fir | loam |
western hemlock | silt |
red alder | silt |
red alder | loam |
Douglas fir | clay |
Douglas fir | sand |
Douglas fir | sand |
Douglas fir | sand |
western hemlock | sand |
Douglas fir | sand |
Douglas fir | clay |
big leaf maple | sand |
Douglas fir | sand |
Douglas fir | sand |
Douglas fir | clay |
big leaf maple | clay |
western hemlock | loam |
red alder | sand |
western redcedar | silt |
Douglas fir | loam |
western hemlock | loam |
western hemlock | clay |
Douglas fir | clay |
Douglas fir | clay |
Douglas fir | loam |
Douglas fir | loam |
Douglas fir | silt |
western hemlock | loam |
Douglas fir | clay |
western redcedar | clay |
western hemlock | sand |
western redcedar | loam |
western hemlock | silt |
big leaf maple | loam |
Douglas fir | clay |
Douglas fir | clay |
Douglas fir | sand |
big leaf maple | silt |
Douglas fir | silt |
Douglas fir | clay |
Douglas fir | silt |
western hemlock | silt |
western hemlock | clay |
western hemlock | loam |
red alder | clay |
Douglas fir | clay |
Douglas fir | silt |
western hemlock | loam |
western hemlock | silt |
Douglas fir | clay |
Douglas fir | sand |
Douglas fir | loam |
Douglas fir | silt |
western redcedar | clay |
big leaf maple | clay |
Douglas fir | sand |
big leaf maple | silt |
Douglas fir | silt |
western hemlock | silt |
Douglas fir | loam |
red alder | loam |
Douglas fir | loam |
Douglas fir | silt |
Douglas fir | clay |
red alder | clay |
Douglas fir | silt |
western hemlock | loam |
western hemlock | loam |
western hemlock | loam |
Douglas fir | clay |
Douglas fir | silt |
Douglas fir | silt |
western hemlock | silt |
western hemlock | clay |
Douglas fir | sand |
western hemlock | sand |
western redcedar | clay |
western hemlock | sand |
Douglas fir | silt |
Douglas fir | loam |
western hemlock | clay |
big leaf maple | sand |
western hemlock | loam |
red alder | loam |
western hemlock | loam |
Douglas fir | loam |
big leaf maple | clay |
Douglas fir | clay |
big leaf maple | silt |
Douglas fir | loam |
western redcedar | sand |
western hemlock | loam |
western hemlock | clay |
Douglas fir | loam |
western hemlock | clay |
Douglas fir | clay |
Douglas fir | loam |
western hemlock | clay |
western hemlock | clay |
Douglas fir | loam |
Douglas fir | loam |
western hemlock | loam |
big leaf maple | loam |
western hemlock | silt |
western hemlock | clay |
Douglas fir | silt |
Douglas fir | sand |
western hemlock | clay |
western hemlock | silt |
Douglas fir | loam |
western hemlock | silt |
western hemlock | silt |
western redcedar | loam |
western hemlock | sand |
Douglas fir | sand |
Douglas fir | clay |
big leaf maple | clay |
Douglas fir | clay |
western redcedar | clay |
Douglas fir | loam |
Douglas fir | silt |
Douglas fir | clay |
western hemlock | loam |
Douglas fir | loam |
western hemlock | loam |
Douglas fir | sand |
Douglas fir | silt |
western hemlock | loam |
western redcedar | sand |
western hemlock | silt |
Douglas fir | loam |
western redcedar | clay |
Douglas fir | loam |
western hemlock | sand |
western hemlock | silt |
western redcedar | loam |
Douglas fir | silt |
Douglas fir | loam |
western hemlock | sand |
Douglas fir | silt |
big leaf maple | loam |
big leaf maple | loam |
western hemlock | clay |
Douglas fir | silt |
Douglas fir | silt |
Douglas fir | clay |
Douglas fir | sand |
Douglas fir | loam |
western hemlock | loam |
red alder | clay |
western hemlock | sand |
Douglas fir | sand |
western hemlock | silt |
western redcedar | loam |
Douglas fir | clay |
Douglas fir | sand |
Douglas fir | silt |
big leaf maple | loam |
western hemlock | sand |
big leaf maple | sand |
western hemlock | sand |
western hemlock | clay |
Douglas fir | silt |
western redcedar | silt |
western hemlock | clay |
western redcedar | clay |
Douglas fir | clay |
big leaf maple | clay |
Douglas fir | loam |
red alder | sand |
Douglas fir | loam |
western redcedar | clay |
western hemlock | clay |
western hemlock | clay |
Douglas fir | clay |
western hemlock | clay |
Douglas fir | loam |
Douglas fir | silt |
Douglas fir | silt |
Douglas fir | sand |
Douglas fir | silt |
Douglas fir | sand |
Douglas fir | sand |
western hemlock | loam |
Douglas fir | clay |
Douglas fir | loam |
Douglas fir | loam |
western redcedar | sand |
big leaf maple | sand |
Douglas fir | silt |
western hemlock | loam |
Douglas fir | sand |
Douglas fir | sand |
western redcedar | clay |
Douglas fir | clay |
western hemlock | loam |
western hemlock | loam |
Douglas fir | loam |
Douglas fir | clay |
Douglas fir | clay |
western hemlock | silt |
Douglas fir | silt |
Douglas fir | silt |
western hemlock | sand |
Douglas fir | sand |
western hemlock | loam |
big leaf maple | clay |
Douglas fir | silt |
big leaf maple | silt |
Douglas fir | silt |
Douglas fir | loam |
western hemlock | loam |
big leaf maple | clay |
western hemlock | silt |
big leaf maple | sand |
Douglas fir | sand |
Douglas fir | clay |
Douglas fir | clay |
western hemlock | silt |
western hemlock | sand |
Douglas fir | loam |
Douglas fir | loam |
Douglas fir | loam |
Douglas fir | sand |
Douglas fir | sand |
big leaf maple | clay |
Douglas fir | clay |
western hemlock | silt |
western redcedar | loam |
western hemlock | silt |
Douglas fir | loam |
red alder | loam |
western hemlock | loam |
big leaf maple | sand |
Douglas fir | sand |
Douglas fir | loam |
Douglas fir | loam |
western redcedar | silt |
Douglas fir | silt |
Douglas fir | loam |
Douglas fir | sand |
western hemlock | loam |
western hemlock | clay |
Douglas fir | loam |
big leaf maple | sand |
Douglas fir | silt |
western redcedar | loam |
western hemlock | loam |
Douglas fir | silt |
western hemlock | loam |
western hemlock | sand |
Douglas fir | sand |
Douglas fir | loam |
Douglas fir | loam |
Douglas fir | clay |
Douglas fir | sand |
western redcedar | silt |
Douglas fir | sand |
western redcedar | clay |
Douglas fir | silt |
western hemlock | silt |
western redcedar | sand |
western hemlock | sand |
Douglas fir | sand |
Douglas fir | loam |
western hemlock | silt |
Douglas fir | clay |
western hemlock | sand |
big leaf maple | clay |
western hemlock | loam |
western hemlock | loam |
Douglas fir | sand |
Douglas fir | sand |
western hemlock | loam |
Douglas fir | clay |
western hemlock | sand |
western hemlock | loam |
red alder | sand |
big leaf maple | silt |
western redcedar | loam |
Douglas fir | clay |
Douglas fir | silt |
Douglas fir | clay |
western hemlock | silt |
western redcedar | sand |
western hemlock | silt |
western hemlock | sand |
big leaf maple | sand |
Douglas fir | loam |
western redcedar | sand |
red alder | loam |
Douglas fir | silt |
Douglas fir | sand |
Douglas fir | loam |
western hemlock | sand |
Douglas fir | sand |
western hemlock | silt |
Douglas fir | sand |
Douglas fir | loam |
red alder | clay |
Douglas fir | loam |
Douglas fir | clay |
western hemlock | clay |
western hemlock | silt |
western hemlock | clay |
Douglas fir | silt |
big leaf maple | clay |
western hemlock | loam |
Douglas fir | silt |
Douglas fir | loam |
western hemlock | clay |
western redcedar | clay |
Douglas fir | loam |
Douglas fir | sand |
Douglas fir | loam |
western hemlock | silt |
western hemlock | silt |
Douglas fir | silt |
Douglas fir | sand |
Douglas fir | silt |
Douglas fir | sand |
Douglas fir | sand |
western hemlock | clay |
big leaf maple | clay |
western hemlock | sand |
western hemlock | loam |
Douglas fir | sand |
Douglas fir | loam |
Douglas fir | sand |
red alder | clay |
Douglas fir | silt |
Douglas fir | loam |
red alder | loam |
western hemlock | silt |
Douglas fir | sand |
Douglas fir | loam |
western hemlock | loam |
western hemlock | sand |
big leaf maple | loam |
western hemlock | loam |
western hemlock | silt |
Douglas fir | silt |
western hemlock | loam |
Douglas fir | sand |
western hemlock | loam |
western redcedar | loam |
Douglas fir | sand |
western hemlock | loam |
Douglas fir | clay |
Douglas fir | clay |
Douglas fir | sand |
western hemlock | sand |
Douglas fir | clay |
western hemlock | loam |
western redcedar | loam |
big leaf maple | sand |
Douglas fir | sand |
western hemlock | loam |
Douglas fir | silt |
western hemlock | loam |
Douglas fir | clay |
big leaf maple | clay |
western hemlock | sand |
Douglas fir | sand |
western hemlock | loam |
Douglas fir | sand |
Douglas fir | loam |
western hemlock | clay |
western hemlock | loam |
Douglas fir | clay |
Douglas fir | silt |
big leaf maple | silt |
Douglas fir | sand |
western hemlock | clay |
western hemlock | loam |
western hemlock | clay |
western hemlock | clay |
Douglas fir | loam |
western hemlock | sand |
Douglas fir | silt |
Douglas fir | clay |
Douglas fir | clay |
big leaf maple | silt |
western hemlock | sand |
Douglas fir | loam |
Douglas fir | silt |
Douglas fir | loam |
Douglas fir | sand |
western hemlock | sand |
western redcedar | sand |
Douglas fir | sand |
western hemlock | sand |
Douglas fir | silt |
Douglas fir | sand |
western hemlock | loam |
red alder | silt |
red alder | silt |
western redcedar | sand |
Douglas fir | silt |
Douglas fir | loam |
western hemlock | sand |
big leaf maple | sand |
Douglas fir | loam |
Douglas fir | loam |
Douglas fir | loam |
western redcedar | clay |
Douglas fir | loam |
red alder | silt |
Douglas fir | sand |
western redcedar | sand |
Douglas fir | sand |
Douglas fir | sand |
western hemlock | loam |
Douglas fir | clay |
western hemlock | silt |
western hemlock | sand |
western hemlock | silt |
big leaf maple | clay |
Douglas fir | sand |
Douglas fir | sand |
Douglas fir | loam |
western hemlock | sand |
western hemlock | sand |
big leaf maple | loam |
western redcedar | clay |
red alder | loam |
big leaf maple | silt |
western hemlock | clay |
big leaf maple | sand |
Douglas fir | clay |
western hemlock | clay |
western redcedar | clay |
Douglas fir | sand |
Douglas fir | sand |
western hemlock | loam |
Douglas fir | clay |
western hemlock | clay |
western redcedar | clay |
Douglas fir | loam |
western hemlock | loam |
Douglas fir | sand |
western redcedar | clay |
western redcedar | sand |
western hemlock | clay |
western redcedar | sand |
western redcedar | silt |
Douglas fir | loam |
western hemlock | sand |
Part 1. Chi-squared Goodness-of-Fit Test
A private landowner has contracted with a logging company to harvest trees from their property. A condition of the contract is that following the harvest, the remaining trees on the property must be composed of the following percentages:
10% big leaf maple
40% Douglas-fir
5% red alder
30% western hemlock
15% western redcedar
Following the harvest, the private landowner claims that the logging company has violated the terms of the contract. The private landowner conducts a survey on the trees remaining after harvest; these data are in the treesoil.csv dataset under the column Tree.
(1a) What is Ho and Ha in a test of the claim?
(1b) Determine how many trees of each species were observed in the survey. Make a frequency table of the tree species data using the table() command. Paste in your frequency table below.
(1c) Use your observed frequencies for each tree species from (1b) to test Ho using a Chi-squared goodness-of-fit test:
chisq.test(dataset, p = c(expected frequencies))
Paste your code and output below.
(1d) Based on your output from (1c), what is your statistical conclusion and interpretation at alpha = 0.05?
Part 2. Chi-squared Test of Independence
In the survey, the private landowner also collected information on the type of soil in which each tree was growing; these data are in the treesoil.csv dataset under the column Soil.
(2a) What is Ho and Ha in a Chi-squared test of independence for the relationship between tree species and soil type?
(2b) Use R/RStudio to make a contingency table of tree species by soil type using table() command. Paste your code and table below.
(2c) Make a mosaic plot in R/RStudio from your contingency table using mosaicplot(). Add an appropriate title, and appropriate labels for the x-axis and y-axis. Use different colors in your plot using col = c("color1", "color2"...); you will need a different color for each column of data in your contingency table. Recall that contingency tables are described as r x c; for example, a 2 x 3 contingency table has 2 rows and 3 columns. Paste your mosaic plot below.
(2d) Based on the mosaic plot from (2c), do you think there is an association between tree species and soil type? Justify your answer.
(2e) Conduct a Chi-squared test of independence to test your hypotheses in (2d). Paste your code and output below.
(2f) Based on your output from (2e), what is your statistical conclusion and interpretation at alpha = 0.05?
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