ESP 161 Lecture 8: 13 Water Quality Laws

Which of the following best illustrates the relationship between entities and attributes?

1. the entity CUSTOMER with the attribute PRODUCT
2. the entity CUSTOMER with the attribute PURCHASE
3. the entity PRODUCT with the attribute PURCHASE
4. the entity product with the attribute CUSTOMER

write an expression that evaluates to true if the str associated with s starts with "p".

In a small study, 12 women with cervical cancer (cancer of the cervix) and 12 women with no apparent cervical cancer were contacted and asked whether they had ever used the hormone estrogen as a drug. Each woman with cancer was matched by age, race, and weight with a woman without the disease. This is an example of:

a) A randomized controlled trial

b)A prospective cohort study

c) A case-control study

d) A retrospective cohort study