The daily distances cycled by 40 couriers are shown in the table…

Contributed by StemPy Lab

Try it on paper first. A hint, the key idea and the worked solution are here when you need them.

The daily distances cycled by $40$ couriers are shown in the table. The classes are equal in width.

Distance (km)	Couriers
20-40	3
40-60	8
60-80	15
80-100	10
100-120	4

Use the step deviation method with $a = 70$ to find the mean distance.

Need a reminder? The key ideaShow

With equal class width $h$ , the step deviation is $u = \dfrac{x - a}{h}$ and

\displaystyle \bar{x} = a + h \times \dfrac{\sum fu}{\sum f}.

When a frequency is missing, write the mean as an equation in the unknown and solve it.

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.

← All Problems

← Forty buses ran the distances in the table below…A teacher records the minutes of reading that each student in a class did in a week, and groups the… →

More onStatistics and Probability › Statistics

Discussion (0)

Loading…