Harmonic Mean

The harmonic mean is a specialised measure of location used only when data consists of a set of rates such as prices (K/kilo), speeds (Kmph) or productivity (output/man hour)

The harmonic mean (hm) is given by:

EXERCISES:

1. Discuss the advantages and disadvantages of each of the measures of central tendency that we have covered.

2. The times (in minutes) taken to repair a particular item in a service department are listed below.

23
24
35
21
46
18
26
25
10
23
20
20
24
56
19
21
25
28
19
17
30
25
20
18
11
42
27
25
23
22
22
17
28
30
31
62
19
17
26
23
24
20
20
31
34
18
26
21

(a) What are the median and the mean, calculate from raw data?
(b) Group the data into a frequency table and estimate the median and the mean from the grouped data.
(c) What are the circumstances in which it would be appropriate to use each measure?