A group of estate agents recorded the time spent on the first meeting with a random sample of 120 of their clients. The times, to the nearest minute, are summarised in the table. a Calculate estimates of the mean and variance of the times. b By interpolation obtain estimates of the median and quartiles of the times spent with customers. 3(mean - median) One measure of skewness is found using standard deviation c Evaluate this measure and describe the skewness of these data. The estate agents are undecided whether to use the median and quartiles, or the mean and standard deviation to summarise these data. d State, giving a reason, which you would recommend them to use.AppendixLO1

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Number Time of clients 10-15 2 15-20 5 20-25 17 25-30 38 30-35 29 35-45 25 45-80 4 Total 120