Answer:
c)
Step-by-step explanation:
The definition of an observational study is: one where researchers observe the effect of a risk factor or an intervention but they do not try to change who is exposed to the factor.
In this particular example, the researchers administered a questionnaire to 391 twelve-year-old and concluded that the body mass index of the adolescents who had a supply of sugary snacks in their bedroom was significantly higher than that of the adolescents who did not have a supply of sugary snacks in their bedroom.
This is not an observational study because the researchers actually administered a questionnaire and analyzed the results. To be an observational study the individuals would have been observed without any intervention (the questionnaire could have had an effect on the adolescents changing their habits)
Answer:
A. The distance from any point in the circle to the origin
Step-by-step explanation:
The distance formula tells you that the distance (d) is related to the coordinates of two points (x1, y1) and (x2, y2) by ...
d² = (x2 -x1)² +(y2 -y1)²
For points (x, y) on the circle and (0, 0) at the origin, this becomes ...
d² = (x -0)² +(y -0)²
If we want the distance to the point (x, y) to be equal to the radius of the circle, this becomes ...
x² +y² = r² . . . . . . the standard equation of a circle centered at the origin
Answer:
A soccer field is 100 Yards.
Step-by-step explanation:
120-100=100yds.
