题目如下：3. We will compare two cases:
(a) When the evaluation score (i.e. # ofstarts) from the most recent previous comment made for the same restaurant isHIGH (= four stars and more)
(b) When the evaluation score (i.e. # ofstarts) from the most recent previous comment made for the same restaurant isLOW (= less than four stars)
Create a new variable that indicates either(a) or (b) for each row in the same data set.
(a) When the evaluation score (i.e. # ofstarts) from the most recent previous comment made for the same restaurant isHIGH (= four stars and more)
(b) When the evaluation score (i.e. # ofstarts) from the most recent previous comment made for the same restaurant isLOW (= less than four stars)
Create a new variable that indicates either(a) or (b) for each row in the same data set.
