Currently there are three types of e-book readers, with very different characteristics, available in the market: 1) the Apple Action (A), 2) the Banana Book (B) and 3) the Cloudberry Cloud (C). Your four main criteria in a good e-book reader are light weight (C1), good features (C2), low cost (C3) and excellent usability (C4). You rate the importance of these four criteria as follows: C1 vs C2 as 5, C1 vs C3 as 3 and C1 vs C4 as 7, C2 vs C4 as 5, C3 vs C2 as 3 and C3 vs C4 as 6. You rate each of the readers as follows.

With respect to weight, A is much lighter (6) than B and almost absolutely lighter (8) than C (in spite of its name). Similarly B is considerably lighter (4) than C. In terms of features, A is much better than B (7), but C (with cloud computing) is essentially better (5) than A. C is almost absolutely better (8) than B. In terms of cost, A is almost absolutely cheaper (8) than B, much cheaper (6) than C, and C is cheaper than B (4). In terms of usability, A is better than B (5), more than slightly better than C (4) and C is slightly better (3) than B.

Based on all this information, which is the best e-book reader to acquire? What is the consistency in your analysis?

## Expert Answer

Alternatives | Criteria | |||||

Weights (total = 1) | 0.40 | 0.15 | 0.15 | 0.30 | ||

E Book name | C1 Light Weight | C2 Good features | C3 Lower Cost | C4 Usability excellence | ||

A1 | A Apple Action | 6 | 7 | 8 | 5 | |

A2 | B Banana Book | 4 | 8 | 4 | 3 | |

A3 | C Cloudberry Cloud | 8 | 5 | 6 | 4 |

Assume A = collection of alternatives – here we can choose one among the 3 e books – namely Apple, Banana or the cloud – A, B, or C

Assume G = collection of goals

The idea of analysis is to find the optimal choice A* with the maximum utility in terms of the desirability in the set of goals.

The weighted sum model (WSM) using the additive utility assumption:

WSM score for A1: 0.40*6 + 0.15*7 + 0.15*8 + 0.30 * 5 = 6.15

WSM score for A2: 0.40*4 + 0.15 *8 + 0.15*4 + 0.30*3 = 4.3

WSM score for A3: 0.40*8 + 0.15 *5 + 0.15*6 + 0.30* 4= 6.05

The maximum score is 6.15 hence the choice A1 that is Apple Action e book reader is the best buy for a consumer

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