833
Seravalle____________Chiesanuova______________San Marino
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982
so the distance from Chiesanuova to Serravalle is :
982 - 833 = 149 miles <==
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: 0.0001
It is unlikely to have a month with no aircraft accidents .
Step-by-step explanation:
Given : Mean number of aircraft accidents = 9 per month
The Poisson distribution formula :-
, where 
is the mean of the distribution.
If X = the number of aircraft accidents per month, then the probability that in a month, there will be no aircraft accidents will be :-
Hence, the probability that in a month, there will be no aircraft accidents = 0.0001
Since this is less than 0.5 , therefor it is unlikely to have a month with no aircraft accidents .
