Answer:
df refers to degrees of freedom.
the specific value of df in the example is 21.
Step-by-step explanation:
In statistics, <em>degrees of freedom</em> is the number of values in the final calculation of a statistic that are free to vary. It is the number of independent ways by which a dynamic system can move, without violating any constraint imposed on it.
In other words,<em> degrees of freedom is </em>the number of independent pieces of information that went into calculating the estimate, and calculated by
n – 1 where “n” is the number of items in your set.
In the question, a simple random sample of 22 speeds of cars on California Highway 405 is to be used to test the claim, thus the number of items in the survey are 22.
From this we get:
df=22-1=21
That answer is D because if you add all of the given angles together (90+54) then subtract it from 180 you get 36 which would be the missing angle on the bottom corner and it is the same angle as the other triangle
Refer to the diagram shown below.
At an arbitrary point P (x,y) on the parabola, the distance, d, from the focus to P should be equal to the distance from P to the directrix.
That is,
d² = (x - 3)² + (y - 4)² = (y - 1)²
(x - 3)² + y² - 8y + 16 = y² - 2y + 1
(x - 3)² + 15 = 6y
Divide each side by 6 to obtain
y = (1/6) (x - 3)² + 5/2
The vertex of the parabola is at (3, 5/2).
The line of symmetry is x = 3.
The leading coefficient, 1/6, is positive, therefore the curve opens upward.
Answer:
X= 10. Should be pretty easy