A study of the effects of a chemical additive on soil acidity recorded the soil acidity of eight plots of land before and after the application of the additive. The results were:

$\begin{array}{|l|l|l|l|l|l|l|l|l|}
\hline \text { Plot } & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 \
\hline \text { Before } & 10 & 8 & 9 & 7 & 8 & 6 & 9 & 11 \
\hline \text { After } & 8 & 7 & 7 & 8 & 6 & 6 & 8 & 8 \
\hline & & & & & & & & \
\hline
\end{array}$

The test value for the sign test is:
A) 1
B) 2
C) 3
D) 4

Question

A study of the effects of a chemical additive on soil acidity recorded the soil acidity of eight plots of land before and after the application of the additive. The results were:

$\begin{array}{|l|l|l|l|l|l|l|l|l|}
\hline \text { Plot } & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 \
\hline \text { Before } & 10 & 8 & 9 & 7 & 8 & 6 & 9 & 11 \
\hline \text { After } & 8 & 7 & 7 & 8 & 6 & 6 & 8 & 8 \
\hline & & & & & & & & \
\hline
\end{array}$

The test value for the sign test is:
A) 1
B) 2
C) 3
D) 4

Quizplus · Accepted Answer

The sign test is a non-parametric test that is used to compare the medians of two related samples. In this case, the two samples are the soil acidity before and after the application of the chemical additive. The test value for the sign test is the number of positive differences between the two samples. In this case, there are 4 positive differences (plots 1, 2, 3, and 8), so the test value is 4.

A Study of the Effects of a Chemical Additive on Soil