13.40 [EX13-40] Sugar beet growers are interested in realizing higher yields and higher sucrose percentages from their crops. But do they go together?

The data that follow are from the Montana 2003 sugar beet crop—values listed are by county, yield is tons per acre, and sucrose is percentage of sucrose.

a. What, if any, relationship do you expect to find between the yield per acre and the sucrose percentage for sugar beets?

b. Draw the scatter diagram for yield in tons per acre (x) and sucrose percentage (y) for the Montana data. Describe the relationship as seen on the scatter diagram. Is it what you anticipated?

c. Find the linear correlation coefficient.

d. At the 0.05 level of significance, is the linear correlation coefficient significantly different than zero?

e. One of the ordered pairs appears to be outside of the pattern created by the other 11 ordered pairs. What effect do you think removal of this pair from the data values would have on (1)
the appearance of the scatter diagram, (2) the linear correlation coefficient, and (3) the answer in part d?

f. Remove Carbon county from the data and answer parts b–d. Compare the results with your answers to part e.

Transcribed Image Text:

County Yield Sucrose County Yield Sucrose Northeast South Central Dawson 20.9 18.94 Yellowstone 25.9 16.71 Richland 24.5 19.67 Other 27.4 16.35 Roosevelt 21.0 19.25 Southeast South Central Custer 21.8 18.96 Big Horn 29.7 16.41 Prairie 22.2 19.58 Carbon 22.7 16.56 Rosebud 31.3 17.10 Treasure 29.4 17.07