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A grain researcher is developing a new variety of wheat. They would like to know

ID: 2947105 • Letter: A

Question

A grain researcher is developing a new variety of wheat. They would like to know if the new strain has a higher yield than the current variety. The randomly select 20 individual 1 acre plots on which to plant the wheat. The randomly assign the new variety to 8 plots and assign the current variety to 12 plots. The mean yield for the new variety is 53.6 bushels per acre with a standard deviation of 5.8 bushels. The mean yield for the current variety is 48.9 with a standard deviation of 5 bushels per acre. a. Determine the value of the pooled standard deviation, sp(round answer to two decimal places b. Determine the value of the test statistic t = (Round your answet to 2 decimal places)

Explanation / Answer

n1 = 8
n2 = 12
x1bar = 53.6
x2bar = 48.9
sigma1 (s1) = 5.8
sigma2 (s2) = 5.0

a)
Sp = sqrt(((n1-1)*s1^2+(n2-1)*s2^2)/(n1+n2-2))
Sp = sqrt((7*5.8 + 11*5)/18)
Sp = 2.30

b)
SE = 2.3*sqrt(1/8 + 1/12)
SE = 1.05

t = (53.6 - 48.9)/1.05
t = 4.48