OlmekinjP
2020-11-12
Answered

The ability to estimate the volume of a tree based on a simple measurement, such as the tree’s diameter, is important to the lumber industry, ecologists, and conservationists. Data on volume, in cubic feet, and diameter at breast height, in inches, for 70 shortleaf pines were reported in C. Bruce and F. X. Schumacher’s Forest Mensuration (New York: McGraw-Hill, 1935) and analyzed by A. C. Akinson in the article “Transforming Both Sides of a Tree” (The American Statistician, Vol. 48, pp. 307–312).
a) Obtain a scatterplot for the data.
b) Decide whether finding a regression line for the data is reasonable. If so, then also do parts (c)-(f).
c) Determine and interpret the regression equation for the data.
d) Identify potential outliers and influential observations.
e) In case a potential outlier is present, remove it and discuss the effect.
f) In case a potential influential observation is present, remove it and discuss the effect.

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asked 2021-02-22

Use the technology of your choice to do the following tasks.
In the article “Statistical Fallacies in Sports” (Chance, Vol. 19, No. 4, pp. 50-56), S. Berry discussed, among other things, the relation between scores for the first and second rounds of the 2006 Masters golf tournament. You will find those scores on the WeissStats CD. For part (d), predict the secondround score of a golfer who got a 72 on the first round.
a) Construct and interpret a scatterplot for the data.
b) Decide whether finding a regression line for the data is reasonable. If so, then also do parts (c)–(f).
c) Determine and interpret the regression equation.
d) Make the indicated predictions.
e) Compute and interpret the correlation coefficient.
f) Identify potential outliers and influential observations.

asked 2021-01-30

Polychlorinated biphenyls (PCBs), industrial pollutants, are known to be a great danger to natural ecosystems. In a study by R. W. Risebrough titled “Effects of Environmental Pollutants Upon Animals Other Than Man” (Proceedings of the 6th Berkeley Symposium on Mathematics and Statistics, VI, University of California Press, pp. 443-463), 60 Anacapa pelican eggs were collected and measured for their shell thickness, in millimeters (mm), and concentration of PCBs, in parts per million (ppm).
a) Obtain a scatterplot for the data.
b) Decide whether finding a regression line for the data is reasonable. If so, then also do parts (c)–(f).
c) Determine and interpret the regression equation for the data.
d) Identify potential outliers and influential observations.
e) In case a potential outlier is present, remove it and discuss the effect.
f) In case a potential influential observation is present, remove it and discuss the effect.

asked 2021-11-16

Make a scatterplot for the data below on the number of people working on farms in various years, and draw a line of best fit. Describe the correlation as strong positive, strong negative, or little to none.

$$\begin{array}{|ccccccc|}\hline Year& 1940& 1950& 1960& 1970& 1980& 1990\\ \text{Number of farm workers in thousands}& 8995& 6858& 4132& 2881& 2818& 2864\\ \hline\end{array}$$

asked 2021-01-31

The Information Please Almanac provides data on the ages at inauguration and of death for the presidents of the United States. We give those data on the WeissStats CD for those presidents who are not still living at the time of this writing.
a) Obtain a scatterplot for the data.
b) Decide whether finding a regression line for the data is reasonable. If so, then also do parts (c)-(f).
c) Determine and interpret the regression equation for the data.
d) Identify potential outliers and influential observations.
e) In case a potential outlier is present, remove it and discuss the effect.
f) In case a potential influential observation is present, remove it and discuss the effect.

asked 2022-03-26

asked 2021-07-04

Using the daily high and low temperature readings at Chicago's O'Hare International Airport for an entire year, a meteorologist made a scatterplot relating y = high temperature to x = low temperature, both in degrees Fahrenheit.

After verifying that the conditions for the regression model were met, the meteorologist calculated the equation of the population regression line to be

If the meteorologist used a random sample of 10 days to calculate the regression line instead of using all the days in the year, would the slope of the sample regression line be exactly 1.02? Explain your answer.

asked 2021-02-24

The document Arizona Residential Property Valuation System, published by the Arizona Department of Revenue, describes how county assessors use computerized systems to value single-family residential properties for property tax purposes.
a) Obtain a scatterplot for the data.
b) Decide whether finding a regression line for the data is reasonable. If so, then also do parts (c)-(f).
c) Determine and interpret the regression equation for the data.
d) Identify potential outliers and influential observations.
e) In case a potential outlier is present, remove it and discuss the effect.
f) In case a potential influential observation is present, remove it and discuss the effect.