One of nature's patterns connects the percent of adult birds in a colony that return from the previous year and the number of new adults that join the colony. Here are data for 13 colonies of sparrowhawks:

Data set You saw in Exercise 4.28 that there is a moderately strong linear relationship, correlationr= 0.748.

Step 1: Find the least-squares regression line for predictingyfromx. Make a scatterplot and draw your line on the plot. Choose the correct line below:

y= 57.79 0.748x

y= 9.41 + 0.406x

y= 31.9 0.304x

y= 24.89 0.183x

Step 2: Explain in words what the slope of the regression line tells us.

On the average, for every 1% increase in returning birds, the number of new birds joining the colony decreases by 0.304.

On the average, for every increase by one in the number of returning birds, the number of new birds joining the colony decreases by 0.304.

On the average, for every 1% increase in returning birds, the number of new birds joining the colony decreases by 0.304%.

On the average, for every 1% decrease in returning birds, the number of new birds joining the colony decreases by 0.304.

Step 3: An ecologist uses the line, based on 13 colonies, to predict how many new birds will join another colony, to which 60% of the adults from the previous year return. What is the prediction? Use the regression line that you selected in Step 1. Give your answer to 2 decimal places.