Conditional Probability (3 of 9: Forensic Statistics)

[geoffiida]

You ran into a slight problem at the end of your analysis when you came up with the result that there was a “1000% chance” the suspect committed the crime. Simple fix: You need to use odds instead of probabilities when working with the Bayes factor/likelihood ratio. You should express your prior odds as 1 to 999 and your posterior odds as 1, 000, 000 to 999. Converting back to percentages, your prior probability is 0.1% (as you correctly stated), and your posterior probability is 1, 000, 000/1, 000, 999 = 99.9%