3) In a study of genetic variation in sugar maple, seeds were collected from native trees in the

eastern United States and Canada and planted in a nursery in Wooster, Ohio. The time of

leafing out of these seedlings can be related to the latitude and mean July temperature of the

place of origin of the seed. The variables are X1 = latitude, X2 = July mean temperature, and

Y = weighted mean index of leafing out time. (Y is a measure of the degree to which the leafing

out process has occurred. A high value is indicative that the leafing out process is well

advanced.) The data is below and in the file maple.txt on the course web page. For the following

problem, check assumptions and use transformations if warranted.( maple.txt is on

Blackboard).

(a) Find the regression of LeafIndex on Latitude. Is latitude a useful predictor of leaf index?

(b) Repeat part (a) for the regression of LeafIndex on JulyTemp.

(c) Find the regression of LeafIndex on Latitude and JulyTemp.

LocationLatitude JulyTemp LeafIndex

Quebec46.9566.720.5

NovaScotia45.5464.321.0

NovaScotia45.0061.818.3

Maine45.4265.018.6

Vermont44.5063.518.6

Michigan46.3765.519.8

Michigan45.0367.720.6

Ontario43.0067.919.2

NewYork42.8070.219.8

Michigan42.7071.115.8

Iowa42.4274.414.5

Iowa40.7576.418.5

Illinois41.3875.916.7

Illinois40.3576.413.9

Ohio40.8071.914.3

Ohio40.9274.215.2

Ohio40.3373.016.6

Ohio41.5871.418.2

Pennsylvania41.9269.718.3

Pennsylvania40.1272.613.3

Massachusetts42.7569.220.0

Connecticut42.0068.018.1

Massachusetts42.5570.017.0

Connecticutt41.5072.515.6

Indiana39.2576.715.7

Illinois37.4579.515.4

Virginia38.3369.515.4

Tennessee36.2574.315.8

NorthCarolina35.8068.915.0

Mississippi31.3880.815.9

Georgia32.8381.214.0

Florida30.7581.010.8