Which scatterplot shows a nonlinear association?

The concentration of carbon dioxide (CO2) in the atmosphere is increasing rapidly due to our use of fossil fuels. Because plants use CO2 to fuel photosynthesis, more CO2 may cause trees and other plants to grow faster. An elaborate apparatus allows researchers to pipe extra CO2 to a 30-meter circle of forest. They selected two nearby circles in each of three parts of a pine forest and randomly chose one of each pair to receive extra CO2. The response variable is the mean increase in base area for 30 to 40 trees in a circle during a growing season. We measure this in percent increase per year. Here are one year's data. Pair Control plot Treated plot Treated - Control 9.782 10.647 0.865 2 7.283 9.254 1.971 3 5.712 8.695 2.983 (a) State the null and alternative hypotheses. (Where u is the mean difference, treated minus control.) Но: и На: и ? : Explain clearly why the investigators used a one-sided alternative. The researchers have no preconceived idea what extra CO2 will do to the growth…

A researcher studies water clarity at the same location in a lake on the same dates during the course of a year and repeats the measurements on the same dates 5 years later. The researcher immerses a weighted disk painted black and white and measures the depth (in inches) at which it is no longer visible. The collected data is given in the table below. Complete parts (a) through (c) below Observation 3 4 Date 1/25 3/19 5/30 7/3 9/13 11/7 Initial Depth, X, 57.1 67.5 70.3 41.2 70.9 44.3 Depth Five Years Later, Y, 54.6 67.7 67.4 41.9 66.6 47.6 a) Why is it important to take the measurements on the same date? O A. Those are the same dates that all biologists use to take water clarity samples. O B. Using the same dates maximizes the difference in water clarity. O C. Using the same dates makes it easier to remember to take samples. O D. Using the same dates makes the second sample dependent on the first and reduces variability in water clarity attributable to date. b) Does the evidence…