Cloning Experiment

Researcher

Professor Richard G Novy, Plant Sciences Department, ND St U

Description

A plant scientist measured the concentration of a particular virus in plant sap using ELISA (enzyme-linked immunosorbent assay) (Novy 1992). The study included 13 potato clones (plants reproduced asexually), with 2 commercial cultivars, 5 somatic hybrids, 5 progeny of the somatic hybrids, and one clone of Solanum etuberosum (a species related to potato). Of the 5 progeny of the somatic hybrids, two were classified as susceptible and three as resistant to the virus. The scientist wants to understand the resistance to the virus among these 13 clones. Plant sap was taken from 5 inoculated plants of each clone, for a total of 65 measurements of titer. Unfortunately, one measurement was lost during processing of the samples. Figure clondat.s shows the raw data by clone. The (a) figure, ordered by clone identifier, indicates considerable range in center and spread but is otherwise not very informative. The (b) figure orders by clone mean, jittered to mitigate overlap, using a separate plot symbol for each clone. The dashed identity line helps track the spread around the mean. This latter plot suggests there is less spread in titer for clones at the extremes than for those in the middle of the range.

Reference

Novy RG (1992) ``Characterization of somatic hybrids between Solanum etuberosum and diploid, tuber-bearing Solanums. PhD Dissertation, Department of Plant Pathology, UW-Madison. 123 pp.

Data & Setup

cloning.dat

clone rep titer code type

cloncrit.dat

critical values for multiple comparisons

cloning.s

read data, one-factor analysis of variance, some contrasts

cloning.sas

SAS code for reading and analysis

Book Figures

clondat.s

B: Concentration by Clone

clonmean.s

B: Plot of Clone Mean vs SD

clonci.s

B: 95% Confidence Intervals by Groups

cloncrit.s

B: Critical Values for Comparison of 13 Clones

clonrng.s

B: Critical Values for Comparison of 9 Clones

clonbont.s

B: Critical Value vs Number of Groups

clonbons.s

B: Bonferroni Comparisons to Match Scheffe' Method

clonres.s

E: Cloning Residuals vs Group Means

clondist.s

E: Cloning Concentration Distribution

clonnorm.s

E: Cloning Normal Probability Plot