There are only four words in the language:awk,yacc,grep, andperl. Each of these words can be either a noun or a verb. Of all noun occurrences, 10% are the wordawk, 20% are the wordyacc, 40% are the wordgrep, and 30% are the wordperl. Of all verb occurrences, 20% are the wordawk, 30% are the wordyacc, 45% are the wordgrep, and 5% are the wordperl.

Using the Markov model described above and the Variable Elimination algorithm, find the probability that the fourth word of the following sentence is a noun:Perl yacc awk awk.

Remember that you can express this sentence with the following Bayes' net:

So in other words, the question is what isP(Q₄=noun| O₁=perl, O₂=yacc, O₃=awk, O₄=awk)?