Chapter 10
1. What is a decision? When does a person have to make a decision?
A decision is a conclusion or resolution reached after a thought out consideration of variables in a problem. When more than one possible action is involved in solving a problem, a decision must be made.
2. Calculating a complex trajectory of a spaceship to Mars is a structured problem, whereas diagnosing the cause of a rash on a person’s skin is often unstructured. How so?
A structured problem is one in which an optimal solution can be reached through a single set of steps. Since the one set of steps is known, and since the steps must be followed in a known sequence, solving a structured problem with the same data always yields the same solution. This sequence of steps is known as an algorithm. An unstructured problem is one for which there is no algorithm to follow to reach an optimal solution— either because there is not enough information about the factors that might affect the solution or because there are so many potential factors that no algorithm can be formulated to guarantee a unique optimal solution. Unstructuredness is closely related to uncertainty.
3. DSSs use models to process data. Explain what a model is. Give an example that is not mentioned in the chapter.
A sequence of events or a pattern of behavior might become a useful model when the relationships among its inputs, outputs, and conditions can be established well enough that they can be used to analyze different parameters. Models are used to predict output on the basis of different input or different conditions or to estimate what combination of conditions and input might lead to a desired output. Models are often based on mathematical research or on experience. A model might be a widely used method to predict performance, such as best- fit linear analysis, or it might be built by the organization, using the experience that employees in the firm have