Question 1
Suppose that you receive a piece of e-mail whose subject line contains the phrase “check this out” (a popular phrase among scammers). Based just on thus and without looking at the sender or the message content, what is the chance that the message is spam? Suppose that 40% of all your emails are spam and the remaining 60% are emails you want to receive. Suppose that 1% of all spam messages contain the phrase “check this out” in their subject lines, while 0.4% of all non- spam messages contain this phrase.
Based on the above data, answer the given subquestions.
What is the total probability of having the phrase “check this out” in subject line of an email?
0.64
0.064
0.0064
0.00064