For the ‘开张典礼’ i.e. ‘opening ceremony’ of Miss Loi’s E-Maths Question of the Day section, here’s a very very very important question that will almost certainly appear in your exam (whatever your school is, wherever you are)!
This hails from the Sec 3 syllabus so Miss Loi reckons this will also be a timely memory refreshment exercise for those you who are now in Sec 4.
Due to complaints of customers snoring away while waiting to be served by the Cashier Aunty, a supermarket conducted a survey to find out the time spent by each of the 500 customers at its payment counter.
| Time (t min) | 0 < t ≤ 1 | 1 < t ≤ 2 | 2 < t ≤ 3 | 3 < t ≤ 4 | 4 < t ≤ 6 |
| No. of customers | 83 | 138 | 140 | 104 | 35 |
- Find the mean time spent by each customer at the Cashier Aunty counter.
- In a frequency distribution histogram drawn, the height of the column representing time t in the interval 4 < t ≤ 6 is 5 cm. Find the column height that represents t in 2 < t ≤ 3.
P.S. Please don’t blame Miss Loi if your own exam question doesn’t have any Cashier Aunty!
