Mongolian desert ants. Refer to the Journal of Biogeography (Dec. 2003) study of ant sites...

Mongolian desert ants. Refer to the Journal of Biogeography (Dec. 2003) study of ant sites in Mongolia, presented in

Mongolian desert ants. The Journal of Biogeography (Dec. 2003) published an article on the first comprehensive study of ants in Mongolia (Central Asia). Botanists placed seed baits at 11 study sites and observed the ant species attracted to each site. Some of the data recorded at each study site are provided in the table on the next page and saved in the GOBIANTS file.

a. Find the mean, median, and mode for the number of ant species discovered at the 11 sites. Interpret each of these values.

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b. Which measure of central tendency would you recommend to describe the center of the number-of-ant-species distribution? Explain.

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c. Find the mean, median, and mode for the percentage of total plant cover at the five Dry Steppe sites only.

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d. Find the mean, median, and mode for the percentage of total plant cover at the six Gobi Desert sites only.

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e. On the basis of the results of parts c and d , does the center of the distribution for total plant cover percentage appear to be different at the two regions?

Based on Pfeiffer, M., et al. “Community organization and species richness of ants in Mongolia along an ecological gradient from steppe to Gobi desert.” Journal of Biogeography, Vol. 30, No. 12, Dec. 2003).

Data on annual rainfall, maximum daily temperature, percentage of plant cover, number of ant species, and species diversity index recorded at each of 11 study sites are saved in the GOBIANTS file.

a. Construct a scatterplot to investigate the relationship between annual rainfall and maximum daily temperature. What type of trend (if any) do you detect?

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b. Use scatterplots to investigate the relationship that annual rainfall has with each of the other four variables in the data set. Are the other variables positively or negatively related to rainfall?

Data on annual rainfall, maximum daily temperature, and number of ant species recorded at each of 11 study sites are listed in the table and saved in the GOBIANTS file

Based on Pfeiffer, M., et al. “Community organization and species richness of ants in Mongolia along an ecological gradient from steppe to Gobi desert.” Journal of Biogeography, Vol. 30, No. 12, Dec. 2003.

a. Consider a straight-line model relating annual rainfall ( y ) and maximum daily temperature ( x ). A MINITAB printout of the simple linear regression is shown below. Give the least squares prediction equation.

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b. Construct a scatterplot for the analysis you performed in part a. Include the least square line on the plot. Does the line appear to be a good predictor of annual rainfall?

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c. Now consider a straight-line model relating number of ant species ( y ) to annual rainfall ( x ). On the basis of the MINITAB printout below. repeat parts a and b .

The data in the GOBIANTS file was used to estimate the straight-line model relating annual rainfall ( y ) to maximum daily temperature ( x ).

a. Give the values of SSE, s2, and s , shown on the MINITAB printout Above.

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b. Give a practical interpretation of the value of s .