Genetics and law of probability when order specified and not specified

Question: What is the probability of a woman who will have 5 children giving birth to four girls and 1 boy in that order? Answer: The probability of giving birth to the first girl is 1/2, as is the second and third girl. [1/2 X 1/2 X 1/2 X 1/2 or (1/2)4] The probability of the last child being a boy is also 1/2. [(1/2)4 X 1/2 = 1/32] Each individual outcome is multiplied by the next because the nature of the question is that of an and question, not an or question. “What is the probability of having a girl and then a boy...“ In terms of how many ways or orders are involved, because only one order is requested by the question, permutations are an unnecessary consideration. The calculated probability is for just one possible order, the one given in the question. Question: What is the probability of a woman who will have 5 children giving birth to four girls and 1 boy? Answer: In this question, the order is not specified. One order would be the way the first question was stated. Its probability was 1/32. Would you expect the probability of any order to be greater than one order? I would. How much greater? The product of the number of different orders and the probability of one order. How many orders could there be for a woman giving birth to four girls and 1 boy? [5!/(4!1!) or 5] The correct answer to the question is 1/32 X 5 or 5/32. The steps are to calculate the probability for one order, then calculate how many orders are possible, and then multiply the probability of one order by the number of possible orders. #phenotype #Genetics101 #mRNA #probability #order #chromosome #GeneticsLecture #aminoAcid #geneExpression #AllelicFrequencies #gametes #centromeres #Cancer #DNA #DNAMolecule #geneticCode #nucleicAcids #tRNA #Genetics #chromatid #GeneticsExamQuestionsSolutions #lawOfProbability #MolecularBiology #GeneticExamQuestionsSolutions #Prokaryotes #genotype #Homozygous #alleles #permutations