Please Help! Naive Bayes Classifier; statistics and Biology! III. Naive Bayes Cl
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Question
Please Help! Naive Bayes Classifier; statistics and Biology!
III. Naive Bayes Classifier: There are two well-known marker genes for breast cancer: BRCA2, ERBB2. Canadian Disease Control Center carried out a clinical trial to check the gene expression levels for these two genes in the subjects diagnosed with breast cancer: one group of 50 randomly recruited subjects has no metastasis; and the other group of 50 subjects has metastasis. After normalization, BRCA2 expression levels follow a normal distribution .N(0, 1) for non-metastatic subjects while N(1, 1) for metastatic subjects. For ERBB2, the corresponding expression levels in non-metastatic subjects and metastic subjects follow normal distributions N(0, 1) and N(-1, 1), respectively. What is the basic assumption of naive Bayes classifier? Under what situations, it may be problematic?Explanation / Answer
The basic assumption of the naive bayes classifier is the independence of the predictor variables. The independence assumption is not a suitable one for realistic models. Because in real life the predictor variables may be correlated (in fact that is the case most of the time),then the assumption of independence fails.