The article “Photocharge Effects in Dye Sensitized Ag[Br,I] Emulsions at Millisecond Range Exposures” (Photographic Science and Engineering [1981]:

138– 144) gave the accompanying data on x 5 % light absorption and y 5 peak photovoltage.

x 4.0 8.7 29.8 30.5 y 0.12 0.28 0.55 0.68 0.85 1.02 1.15 1.34 1.29 a x 5 179.7 a x2 5 4334.41 a y 5 7.28 a y2 5 7.4028 a xy 5 178.683

a. Construct a scatterplot of the data. What does it suggest?

b. Assuming that the simple linear regression model is appropriate, obtain the equation of the estimated regression line. y^ 5 20.08259 1 0.4464x

c. How much of the observed variation in peak photovoltage can be explained by the model relationship?

d. Predict peak photovoltage when percent absorption is 19.1, and compute the value of the corresponding residual.

e. The authors claimed that there is a useful linear relationship between the two variables. Do you agree?
Carry out a formal test.

f. Give an estimate of the average change in peak photovoltage associated with a 1 percentage point increase in light absorption. Your estimate should convey information about the precision of estimation.
g. Give an estimate of mean peak photovoltage when percentage of light absorption is 20, and do so in a way that conveys information about precision.