Answer:
0.292
Step-by-step explanation:
When we select the first widget, there are 20 good widgets from 25 total.
When we select the second widget, there are 19 good widgets from 24 total.
So on and so forth.
So the probability is:
P = (20/25) (19/24) (18/23) (17/22) (16/21)
P = 0.292
Alternatively, we can calculate this using combinations.
We are selecting 5 widgets from a total of 25. ₂₅C₅
From the 5 defective widgets, we want to select 0. ₅C₀
From the 20 non-defective widgets, we want to select 5. ₂₀C₅
So the probability is:
P = (₅C₀ ₂₀C₅) / ₂₅C₅
P = 0.292
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:
whats the question?
Step-by-step explanation:
