Enterprise Industries has been running a television advertisement for Fresh liquid laundry detergent. When a survey was conducted, .21 of the individuals surveyed had purchased Fresh. .41 of the individuals surveyed had recalled seeing the advertisement, and .13 of the individuals surveyed had purchased Fresh and recalled seeing the advertisement.
a. What proportion of the individuals surveyed who recalled seeing the advertisement had purchased Fresh?
b. Based on your answer to part a, does the advertisement seem to have been effective? Explain.