Retaining customers is critical to business success. NPS is used as a metric for customer loyalty, which strongly correlates with revenue growth. Data are obtained via a variant of the simple question "What is the likelihood that you would recommend us?" with the 0-10 score range. Scores of 9 or 10 mean "promoters" and "not price sensitive "; 7 or 8 for "passives"; and, 6 or lower for "detractor" and "price sensitive". We have the following survey data:
Score 0 1 2 3 4 5 6 7 8 9 10
Freq. 1 3 5 4 7 15 22 51 85 73 59
(a) Calculate the percentage of promoters. (b) Calculate the percentage of detractors. (c) Calculate the net promoter score.