Forty mothers have taken the suspected drug during their pregnancies. of these mothers, 35 have delivered malformed infants. in addition, 10 other infants are born with malformations. the number of individuals who both did not take the drug and did not give birth to infants who were malformed was:

The complete question is :

As an epidemiologist you are going to investigate the effect of a drug suspected of causing malformations in newborn infants when the drug in question is taken by pregnant women during the course of their pregnancies. As your sample you will use the next 200 single births occurring in a given hospital. For each birth a medication history will be taken from the new mother and from her doctor; in addition, you will review medical records to verify use of the drug. [N.B.: These mothers are considered to have been followed prospectively during the entire course of their pregnancies, because a complete and accurate record of drug use was maintained during pregnancy.] The resultant data are: Forty mothers have taken the suspected drug during their pregnancies. Of these mothers, 35 have delivered malformed infants. In addition, 10 other infants are born with malfunctions. What is the relative risk between exposure to the drug and malformations?

14

Explanation:

The relative risk is a measure that is used to calculate or compare the likelihood or the chance that an event would occur while comparing the two groups. To calculate the relative risk, the probability of an event occurring in one group is compared with the probability of the event occurring in another group and this is done by dividing the probability of one group by another. The value of relative risk is always either zero or greater than zero but it cannot be negative. The value 1 indicates neutrality.The probability of an event = no. of favorable outcomes/ total no. of outcomesFor the given question, 35 mothers out of 40 delivered infants that were malformed, so the probability of delivering malformed infants is 35/40. Out of the 200 births, 40 have occurred so total births left is 200 - 40 = 160Therefore, the probability of the second event is 10/160. Therefore relative risk is = (35/40)/(10/160) = (0.875/0.062) = 14

When you are making a guess you are forming a hypothesis

Yes yes yes very good