$12\mathrm{.}8(5)$ What classes require state diagrams? Describe some relevant states and events.

Exercises $12\mathrm{.}9-12\mathrm{.}13$ are related. Do the exercises in sequence. These exercises concern a computerized scoring system that you have volunteered to create for the benefit of a local children's synchronized swimming league. Teams get together for competitions called meets during which the children perform in two types of events: figures and routines. Figure events, which are performed individually, are particular water ballet maneuvers such as swimming on your back with one leg raised straight up$.$ Routines, which are performed by the entire team, are water ballets. Both figures and routines are scored, but your system need only address figures.

Each child must provide his or her name, age, address, and team name to register prior to the meet. To simplify scoring, each contestant is assigned a number.

During a meet, figure events are held simultaneously at several stations that are set up around a swimming pool, usually one at each corner. There are volunteer judges and scorekeepers. Scorekeepers tend to tire, so there is often turnover in their ranks. Several judges and scorekeepers are assigned to each station during a meet. Over the course of a season each judge and scorekeeper may serve sev$-$

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Chapter $12/$ Domain Analysis

eral stations. For scoring consistency, each figure is held at exactly one station with the same judges. A station may process several figure events in the course of a meet.

Contestants are organized into groups, with each group starting at a different station. When a child is finished at one station, he or she proceeds to another station for another event. When everyone has been processed at a station for a given event, the station switches to the next event assigned to it$.$

Each competitor gets one try at each event, called a trial. Just before a trial, the child's number is announced to the child and to the scorekeepers. Sometimes the children get out of order or the scorekeepers become confused and the station stops while the problem is fixed. Each judge indicates a raw score for each observed trial by holding up numbered cards. The raw scores are read to the scorekeepers, who record them and compute a net score for the trial. The highest and lowest raw scores are discarded, and the average of the remaining scores is multiplied by a difficulty factor for the figure.

Individual and team prizes are awarded at the conclusion of a meet based on top individual and team scores. There are several age categories, with separate prizes for each category. Individual prizes are based on figures only. Team prizes are based on figures and routines.

Your system will be used to store all information needed for scheduling, registering, and scoring. At the beginning of a season, all swimmers will be entered into the system and a season schedule will be prepared, including deciding which figures will be judged at which meets. Prior to a meet, the system will be used to process registrations. During a meet, it will record scores and determine winners.

$12\mathrm{.}9(3)$ The following is a list of candidate classes for the scoring system. Prepare a list of classes that should be eliminated for any of the reasons given in this chapter. Give a reason for each elimination. If there is more than one reason, give the main one.

address, age, age category, average score, back, card, child, child's name, competitor, compute average, conclusion, contestant, corner, date, difficulty factor, event, figure, file of team member data, group, individual, individual prize, judge, league, leg, list of scheduled meets, meet, net score, number, person, pool, prize, register, registrant, raw score, routine, score, scorekeeper, season, station, team, team prize, team name, trial, try, water ballet.

$12\mathrm{.}10(3)$ Prepare a data dictionary for proper classes from the previous exercise.

$12\mathrm{.}11(4)$ The following is a list of candidate associations and generalizations for the scoring system. Prepare a list of associations and generalizations that should be eliminated or renamed for any of the reasons given in this chapter. Give a reason for each elimination or renaming. If there is more than one reason, give the main one.

a season consists of several meets, a competitor registers, a competitor is assigned a number, a number is announced, competitors are split into groups, a meet consists of several events, several stations are set up at a meet, several events are processed at a station, several judges are assigned to a station, routines and figures are events, raw scores are read, highest score is discarded, lowest score is discarded, figures are processed, a league consists of several teams, a team consists of several competitors, a trial of a figure is made by a competitor, a trial receives several scores from the judges, prizes are based on scores.

$12\mathrm{.}12$ Figure E$12\mathrm{.}4$ is a partially completed class diagram for the scoring system. The association between me