Question: A long term study of changing environmental conditions in Chesapeake Bay found the

following annual average salinity readings in one location in the bay (Excel exam file;

worksheet Question 3):

a. Make a plot of salinity against time. Was salinity generally increasing or decreasing

over these years? Is there an overall straight line trend over time?

b. What is the correlation between salinity and year/ What percentage of the observed

variation in salinity is accounted for by straight line change over time?

c. Find the least squares regression line for predicting salinity from year. Explain in

simple language what the slope of this line tells you about Chesapeake Bay.

d. If the trend in these past data had continued, what would be the average salinity at this

point in the bay in 1988?