6 a 1 + 12 + 24 + 15 + 13 + 9 + 5 = 79 M1 3.1 M1 for addition of frequencies B 79 patients b Total number of minutes = sum of (midpoint M1 M1 for midpoints × frequencies × frequency) for each class = 2754 M1 M1 for total minutes Mean time = = minutes M1 M1 for division of total minutes by total patients (ft) 34.86… c Estimated mean = 35 minutes Modal time = 21–30 minutes= 40 B1 B1 for appropriate rounding to whole minutes The median is the 40th person. Estimate mean waiting time = 35 minutes The 40th person is in the 31–40 group. M1 for mode M1 Median time is 31–40 minutes d For the group who waited over one hour (61–70), there were 5 patients. M1 for median M1 So 74 patients were seen in one hour or A1 for correct, shortest, average waiting time A1 less. The hospital would use the modal time. = 0.9367…. So 93.7% of patients saw a doctor within M1 for calculation of or 1 () as a percentage – one hour. M1 A1 cao A1 93.7% of patients saw a doctor within one hour. 10
6 a b c d 1 + 12 + 24 + 15 + 13 + 9 + 5 = 79 Total number of minutes = sum of (midpoint × frequency) for each class = 2754 Mean time = = 34.86… minutes Estimated mean = 35 minutes Modal time = 21–30 minutes= 40 The median is the 40th person. The 40th person is in the 31–40 group. Median time is 31–40 minutes For the group who waited over one hour (61–70), there were 5 patients. So 74 patients were seen in one hour or less. = 0.9367…. So 93.7% of patients saw a doctor within one hour. 79 patients Estimate mean waiting time = 35 minutes The hospital would use the modal time. 93.7% of patients saw a doctor within one hour. M1 M1 M1 M1 B1 M1 M1 A1 M1 A1 3.1 M1 for addition of frequencies M1 for midpoints × frequencies M1 for total minutes M1 for division of total minutes by total patients (ft) B1 for appropriate rounding to whole minutes M1 for mode M1 for median A1 for correct, shortest, average waiting time M1 for calculation of or 1 – () as a percentage A1 cao B 10
Higher_Skills_Statistics_MarkScheme_AQA.docx