Question

An agricultural scientist planted alfalfa on several plots of land, identical except for the soil pH. Below is a table with the dry matter yields (in pounds per acre) for each plot.

pH	4.6	4.8	5.2	5.4	5.6	5.8	6.0
Yield	1,056	1,833	1,629	1,852	1,783	2,647	2,131

a) what is the slope of the least-squares line for predicting yield from pH is closest to? a)1,405.3 b)1521.5 c)-2090.9 d)-1521.5

b) The y-intercept of the least-squares line for predicting yield from pH is closest to? a)1405.3 b)1521.5 c)-2090.9 d)-1521.5

c) what is the correlation coefficient of the least-squares line for predicting yield from pH is closest to? a)0.6129 b)0.1969 c)0.5354 d)0.7829

d) what is the estimate of s, the error standard deviation, of the least-squares line for predicting yield from pH is closest to?    a)856.9 b)262 c)329 d)570.3

Answer 1

The statistical software output for this problem is :

a)

Slope = 737.1

b)

y-intercept = -2090.9

c)

Correlation coefficient = 0.7829

d)

error standard deviation = 329