Dr. Guinea Pigg would like to test if the amount of caffeine intake would affect how well laboratory rats performed on a specific task. He randomly assigned 40 rats to five groups (n = 8). Each rat walked the same maze after drinking caffeinated water. The amount of caffeine the rats took and the number of mistakes they made in walking the maze were recorded in the following table.

$\begin{array}{crrrrr}
\text { Dosage } & 10 \mathrm{mg} & 20 \mathrm{mg} & 30 \mathrm{mg} & 40 \mathrm{mg} & 50 \mathrm{mg} \
\hline & 16 & 16 & 2 & 5 & 7 \
& 5 & 10 & 9 & 8 & 12 \
& 11 & 7 & 11 & 1 & 14 \
\text { Number of } & 23 & 12 & 13 & 5 & 16 \
\text { mistakes } & 18 & 7 & 10 & 8 & 11 \
& 12 & 4 & 13 & 11 & 9 \
& 12 & 23 & 9 & 9 & 19 \
& 19 & 13 & 9 & 9 & 24 \
\hline
\end{array}$
Using the data, conduct a trend analysis to test if there is any linear, quadratic, or cubic trend ($\alpha$ = .05).

Question

Dr. Guinea Pigg would like to test if the amount of caffeine intake would affect how well laboratory rats performed on a specific task. He randomly assigned 40 rats to five groups (n = 8). Each rat walked the same maze after drinking caffeinated water. The amount of caffeine the rats took and the number of mistakes they made in walking the maze were recorded in the following table.

$\begin{array}{crrrrr}
\text { Dosage } & 10 \mathrm{mg} & 20 \mathrm{mg} & 30 \mathrm{mg} & 40 \mathrm{mg} & 50 \mathrm{mg} \
\hline & 16 & 16 & 2 & 5 & 7 \
& 5 & 10 & 9 & 8 & 12 \
& 11 & 7 & 11 & 1 & 14 \
\text { Number of } & 23 & 12 & 13 & 5 & 16 \
\text { mistakes } & 18 & 7 & 10 & 8 & 11 \
& 12 & 4 & 13 & 11 & 9 \
& 12 & 23 & 9 & 9 & 19 \
& 19 & 13 & 9 & 9 & 24 \
\hline
\end{array}$
 Using the data, conduct a trend analysis to test if there is any linear, quadratic, or cubic trend ($\alpha$ = .05).

Quizplus · Accepted Answer

The Answer is Procedure:
Create a data set with two variables, Dosage and Mistakes. The data set should have 40 cases, each representing one rat.

Go to Analyze

\rightarrow

General Linear Model

\rightarrow

Univariate.
Select Mistakes as the Dependent Variable and Dosage as the Fixed Factor. Go to Contrasts and select Polynomial in the pull-down menu under Change Contrasts. Click Change, then Continue.
To plot the trend, go to Plots, select Dosage to Horizontal Axis. Click Add, then Continue.

Selected SPSS Output:
$Procedure: Create a data set with two variables, Dosage and Mistakes. The data set should have 40 cases, each representing one rat. Go to Analyze \rightarrow General Linear Model \rightarrow Univariate. Select Mistakes as the Dependent Variable and Dosage as the Fixed Factor. Go to Contrasts and select Polynomial in the pull-down menu under Change Contrasts. Click Change, then Continue. To plot the trend, go to Plots, select Dosage to Horizontal Axis. Click Add, then Continue. Selected SPSS Output: A trend analysis was conducted to determine if there was any significant linear, quadratic, or cubic trend in the number of mistakes made as the dosage of caffeine increases ( \alpha = .05). From the summary table, we see that the linear trend was not significant (p =.324), nor was the cubic trend significant (p =.131). However, the quadratic trend was statistically significant (p = .005). The profile plot suggested that the number of mistakes made decreased as the caffeine intake increased from 10 mg to 40 mg, yet increased drastically as the intake further increased to 50 mg.$

$Procedure: Create a data set with two variables, Dosage and Mistakes. The data set should have 40 cases, each representing one rat. Go to Analyze \rightarrow General Linear Model \rightarrow Univariate. Select Mistakes as the Dependent Variable and Dosage as the Fixed Factor. Go to Contrasts and select Polynomial in the pull-down menu under Change Contrasts. Click Change, then Continue. To plot the trend, go to Plots, select Dosage to Horizontal Axis. Click Add, then Continue. Selected SPSS Output: A trend analysis was conducted to determine if there was any significant linear, quadratic, or cubic trend in the number of mistakes made as the dosage of caffeine increases ( \alpha = .05). From the summary table, we see that the linear trend was not significant (p =.324), nor was the cubic trend significant (p =.131). However, the quadratic trend was statistically significant (p = .005). The profile plot suggested that the number of mistakes made decreased as the caffeine intake increased from 10 mg to 40 mg, yet increased drastically as the intake further increased to 50 mg.$
A trend analysis was conducted to determine if there was any significant linear, quadratic, or cubic trend in the number of mistakes made as the dosage of caffeine increases (

\alpha

= .05). From the summary table, we see that the linear trend was not significant (p =.324), nor was the cubic trend significant (p =.131). However, the quadratic trend was statistically significant (p = .005).
The profile plot suggested that the number of mistakes made decreased as the caffeine intake increased from 10 mg to 40 mg, yet increased drastically as the intake further increased to 50 mg.

Dr Guinea Pigg Would Like to Test If the Amount