Sleuth3 (version 0.1-6)

case0402: Cognitive Load

Description

Educational researchers randomly assigned 28 ninth-year students in Australia to receive coordinate geometry training in one of two ways: a conventional way and a modified way. After the training, the students were asked to solve a coordinate geometry problem. The time to complete the problem was recorded, but five students in the conventional group did not complete the solution in the five minute alloted time.

Usage

case0402

source

Ramsey, F.L. and Schafer, D.W. (2013). The Statistical Sleuth: A Course in Methods of Data Analysis (3rd ed), Cengage Learning.

References

Sweller, J., Chandler, P., Tierney, P. and Cooper, M. (1990). Cognitive Load as a Factor in the Structuring of Technical Material, Journal of Experimental Psychology General 119(2): 176--192.

Examples

str(case0402) # level 1 of Treatment is "Conventional" (1st alphabetically)
attach(case0402)  

boxplot(Time ~ Treatment) 
median(Time[Treatment=="Conventional"])-median(Time[Treatment=="Modified"])  
  
wilcox.test(Time ~ Treatment, exact=FALSE, correct=TRUE, 
  alternative="greater")  # Rank-sum test; alternative: group 1 is greater
wilcox.test(Time ~ Treatment, exact=FALSE, correct=TRUE, 
  alternative="two.sided", conf.int=TRUE)  # Use 2-sided to get confidence int.  
        
## DOT PLOTS FOR PRESENTATION 
xTreatment    <- ifelse(Treatment=="Conventional",1,2) # Make numerical values  
myPointCode   <- ifelse(Censored==0,21,24)  
plot(Time ~ jitter(xTreatment,.2),   # Jitter the 1's and 2's for visibility
     ylab="Completion Time (Sec.)",  xlab="Training Method (jittered)",
     main="Test Completion Times from Cognitive Load Experiment",
     axes=FALSE, pch=myPointCode, bg="green", cex=2, xlim=c(.5,2.5) )  
axis(2) # Draw y-axis as usual
axis(1, tick=FALSE,  at=c(1,2),  # Draw x-axis without ticks
  labels=c("Conventional (n=14 Students)","Modified (n=14 Students)") )  
legend(1.5,300, legend=c("Did not Complete in 300 sec","Completed in 300 sec."),
       pch=c(24,21), pt.cex=2, pt.bg="green")  
  
detach(case0402)