Statistically significant changes in gene expression are detected by: fold change p-values correlation coefficient (r) square of the correlation coefficient (r2) QUESTION 16 When observed differences in gene expression are not because of transcriptional changes, they can be due to: different labeling efficiencies of Cy3, Cy 5 uneven spotting of DNA onto an array surface variations in RNA purity or quantity variations in washing efficiency variations in scanning efficiency all of the above For a 2-fold up renulation the log-base2 of the aene emnrasaino rakin between 2 canditions must be than the gene expression ratio between 2 conditionsmust be while for a 2.fold down regudation, the log base? of than QUESTION 21 In order to find patterns of gene expression in a microarray or RNA-seq experiment, one can perform unsupervised learning using [x] QUESTION 22 When two different technicians process samples in an experiment, there may be large differences in expression measurements This is called the [x] effect