
Level
1
Tip 1
The times are not in order.
If they were in order, which would be the middle value?
This time is the median.
Tip 2
The range is the difference between the longest and the shortest
times.
Range = longest time - shortest time
Tip
3
Look at the departure times.
Add on the median time.
Is the time soon enough?
Tip
4
A small range means a reliable train.
Of the trains that arrive soon enough which is most reliable?
Choose this train.
Level 2
Tip 1
Calculate the mean time for each train.
Add the times together and divide by 5.
The answer is the mean.
The mean may be a decimal.
Tip 2
Calculate the range by finding:
Range = longest time - shortest time
A small range means a reliable train.
Tip 3
Look at the departure times.
Add on the mean time.
(Remember that there are 60 mins in 1 hour,
0.2 hours is 12 minutes,
0.4 hours is 24 minutes, etc.)
Tip 4
What if two trains arrive at the same time?
Which has the smallest range?
Choose this train because it is more reliable.
Level 3
Tip
1
Calculate the mean time for each train.
Add the times together and divide by 5.
The answer is the mean.
Tip
2
Calculate the range by finding.
Range = longest time - shortest time
A small range means a reliable train.
Tip
3
Look at the departure times.
Add on the mean time.
Of the trains that arrive soon enough which is most reliable?
Choose this train.
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