Answer:
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Answer:
In studies about new medicines, researchers usually give one group of patients the medicine that is designed to treat an illness. They give another group of patients a placebo, which is taken the same way as the medicine but does not actually contain the ingredients of any medicine. Different medicines are tested in different experiments, but the placebos usually contain the same non-medical ingredients. If both groups of patients are healed, then researchers cannot be sure whether the medicine caused improvement, but if the group given the medicine is healed while the group given the placebo remains ill, researchers can conclude that the medicine causes the illness to go away.
In medical experiments, which group receives placebos?
the experimental group
the control group
both the experimental and control groups
neither the experimental nor control group
Explanation:
Answer:
The use case diagram is attached.
Explanation:
Create a set of use cases for the following health club membership system:
When members join the health club, they pay a fee for a certain length of time. Most memberships are for one year, but memberships as short as two months are available. Throughout the year, the health club offers a variety of discounts on its regular membership prices (e.g., two memberships for the price of one for Valentine's Day). It is common for members to pay different amounts for the same length of membership. The club wants to mail out reminder letters to members asking them to renew their memberships one month before their memberships expire. Some members have become angry when asked to renew at a much higher rate than their original membership contract, so that the clubwants to track the price paid so that the manager can override the regular prices with special prices when members are asked to renew. The system must track these new prices so that renewals can be processed accurately. One of the problems in the healthclub industry is the high turnover rate of members. While some members remain active for many years, about half of the members do not renew their memberships. This is a major problem because the health club spends a lot in advertising to attract each new member. The manager wants the system to track each time a member comes into the club. The system will then identify the heavy users and generate a report so that the manager can ask them to renew their memberships early, perhaps offering them a reduced rate for early renewal. Likewise, the system should identify members who have not visited the club in more than a month so that the manager can call them and attempt to reinterest them in the club.
The use case diagram is attached.