3. (i) Below is the R code for performing a X2 test on a 2×3 matrix of categorical variables called TestMatrix: chisq.test(Test Matrix) (a) Assuming we have a significant result for this procedure, provide the R code (including any required packages) for an appropriate post hoc test. (b) If we were to apply this technique to a 2 × 2 case, how would we adapt the code in order to perform the correct test? (ii) What procedure can we use if we want to test for association when we have ordinal variables? What code do we use in R to do this? What package does this command belong to? (iii) The following code contains the initial steps for a scenario where we are looking to investigate the relationship between age and whether someone owns a car by using frequencies. There are two issues with the code - please state these. Row3<-c(75,15) Row4<-c(50,-10) MortgageMatrix<-matrix(c(Row1, Row4), byrow=T, nrow=2, MortgageMatrix dimnames=list(c("Yes", "No"), c("40 or older","<40"))) barplot(MortgageMatrix, beside=TRUE, ylim c(0, 40), legend-T, col=c("yellow", "blue"), xlab="Earnings", ylab="Frequency") [4 Marks]

3. (i) Below is the R code for performing a X2 test on a 2×3 matrix of categorical variables called TestMatrix: chisq.test(Test Matrix) (a) Assuming we have a significant result for this procedure, provide the R code (including any required packages) for an appropriate post hoc test. (b) If we were to apply this technique to a 2 × 2 case, how would we adapt the code in order to perform the correct test? (ii) What procedure can we use if we want to test for association when we have ordinal variables? What code do we use in R to do this? What package does this command belong to? (iii) The following code contains the initial steps for a scenario where we are looking to investigate the relationship between age and whether someone owns a car by using frequencies. There are two issues with the code - please state these. Row3<-c(75,15) Row4<-c(50,-10) MortgageMatrix<-matrix(c(Row1, Row4), byrow=T, nrow=2, MortgageMatrix dimnames=list(c("Yes", "No"), c("40 or older","<40"))) barplot(MortgageMatrix, beside=TRUE, ylim c(0, 40), legend-T, col=c("yellow", "blue"), xlab="Earnings", ylab="Frequency") [4 Marks]

College Algebra (MindTap Course List)

12th Edition

ISBN:9781305652231

Author:R. David Gustafson, Jeff Hughes

Publisher:R. David Gustafson, Jeff Hughes

Chapter6: Linear Systems

Section6.2: Guassian Elimination And Matrix Methods

Problem 84E: Explain the differences between Gaussian elimination and Gauss-Jordan elimination.

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