The programme aims to reduce body mass. Each entry in the second list belongs to the same person as

Question

The programme aims to reduce body mass. Each entry in the second list belongs to the same person as the corresponding entry in the first list.

Weights before a programme are 74, 68, 62, 57, 81, 76, 69, 64, 72, 66, 59, 83, 71, 65, 77, 70, 63, 75, 80, 67 kg. Afterward they are 69, 64, 58, 54, 76, 72, 65, 61, 68, 62, 56, 78, 67, 61, 72, 66, 60, 70, 75, 63 kg.

Draw a back-to-back stem-and-leaf diagram.[3]
Decide whether the programme was effective and justify.[2]

Accepted Answer

(a) See worked solution. (b) The median decreased from $69.5$ kg to $65.5$ kg and every paired mass decreased. The changes meet the stated aim, but do not alone establish causation.

Before-and-after weight distributions

Before-and-after weight distributions

Solution:

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