The table shows information about the distances 570 students travelled to a university open day - Edexcel - GCSE Maths - Question 18 - 2018 - Paper 3
Question 18
The table shows information about the distances 570 students travelled to a university open day.
Distance (d miles) Frequency
0 < d ≤ 20 ... show full transcript
Worked Solution & Example Answer:The table shows information about the distances 570 students travelled to a university open day - Edexcel - GCSE Maths - Question 18 - 2018 - Paper 3
Step 1
Estimate the median distance.
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Answer
To estimate the median distance from the histogram, we need to find the cumulative frequency and determine the median position.
First, calculate the cumulative frequency:
For 0 < d ≤ 20: 120
For 20 < d ≤ 50: 120 + 90 = 210
For 50 < d ≤ 80: 210 + 120 = 330
For 80 < d ≤ 150: 330 + 140 = 470
For 150 < d ≤ 200: 470 + 100 = 570
The median position is given by:
rac{N}{2} = rac{570}{2} = 285
where N is the total frequency.
Locate the interval containing the 285th student:
The cumulative frequency reaches 210 at the interval 20 < d ≤ 50.
It exceeds 285 in the interval 50 < d ≤ 80 (cumulative frequency of 330).
Hence, the median lies within the interval 50 < d ≤ 80.
Using a proportional method, we can further refine this. Since 285 is 75 into the interval (285 - 210 = 75), we calculate the position within the interval: