Answer:
B. The observational study is a cross-sectional study because information is collected at a specific point in time.
Step-by-step explanation:
1) There are three types of Observational Studies: Case-control, cross-sectional and Cohort.
2) Since the researchers collected information from those 1800 adults at a certain time, then we can call it a cross-sectional study. It does not provide solid results since the research was not done over a period to collect further information. We don't know, for example, much more than what that association deeply mean.
3) If we wonder more, then the researchers would have to track those adults over a given period, i.e. a Cohort would be necessary.
4) Moreover, it's not "retrospective" for virtually every question, always makes us look back somehow, and it does not categorize a kind of observational study.
Answer:
4
x
−
5
+
y
=
0
x
−
y
+
4
=
8
x
+
6
y
=
5
Step-by-step explanation:
Length of the room is 5 m and width is 5 + 2 = 7 m.
Hope this helps.
r3t40
Answer:LetAbe the event that the person is taking the drug. We are told thatP(A) = 0.05.LetBbe the event that the person has migraines. We are told thatP(B) = 0.1.Further, we are told thatP(B|A) = 0.3. Using the rules for conditional probability,P(A|B) =P(A∩B)P(B)=P(B|A)P(A)P(B)=0.3·0.050.1=0.15.The probability that a migraine sufferer takes the drug is 15%.
Step-by-step explanation:
