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.
Area of the sheet used to make the tank = total surface area of the cylinder = 2r(r+h) = 2 x 22/7 x 63 x 263 = 104148 sq. cm.
What are we trying to solve?
If all students scored the same the score of each student would be 4.5.
Answer:
Defining variable: x = per week
Equation: 37 + 6.5x = 9 + 8.25x
Answer: 16 weeks
Step-by-step explanation:
x = per week
Jack:
37 + 6.5x
Diane:
9 + 8.25x
Equation:
37 + 6.5x = 9 + 8.25x
-1.75x = -28
x = 16