EasyStatistics & Data ScienceHigh School (9–10)High School (11–12)UndergraduateGeneralStatistics Basics › Tables and GraphsStatistics Basics › Spread of DataConceptual
A café records the minutes it takes to deliver 40 orders on a made-up day…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A café records the minutes it takes to deliver 40 orders on a made-up day. The histogram has six bins of 10 minutes each, from 0 to 60 minutes. Their heights are 3, 15, 11, 6, 3 and 2. Describe the shape. Which bin is the tallest? On which side is the tail? Suggest one reason why a few deliveries took so long.
Need a reminder? The key ideaShow
Describe a distribution by its shape, centre, spread and unusual features. Skew is named after the long tail. Two peaks often mean two groups mixed together. A gap or an outlier deserves a reason.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. The peak. The tallest bar is 10 to 20 minutes, with 15 orders.
Step 2. The tail. To the right of the peak the bars fall slowly: 11, 6, 3, 2. To the left there is only one short bar. The tail is on the right.
Answer: The distribution is unimodal and skewed right, with its peak at 10 to 20 minutes.
Why the tail? A delivery time cannot be less than zero, but a few orders can be delayed for a long time: heavy traffic, a large order, or a driver sent to the wrong address.
Discussion (0)
Log in to join the discussion.
Loading…