H = m/y + z/y - d
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v
If and only if, which mathematicians abbreviate as iff. no kidding, you could look it up:)
Answer:
The answer is below
Step-by-step explanation:
Given that:
Mean (μ) = 1.93, standard deviation (σ) = 1.08 pounds, sample (n) = 62.
the mean weight of discarded plastic for all household is given by:
The standard deviation of discarded plastic for all household is given by:
The confidence (c) = 90% = 0.9
α = 1 - c = 1 - 0.9 = 0.1
α/2= 0.1/2 = 0.05
The z score of 0.05 corresponds to the z score of 0.45 (0.5 - 0.05) which is 1.645. i.e.
The margin of error (E) =
The confidence interval =
We are 90% confidence that the value is between 1,7044 and 2.1556
Answer:
a = 2, b = -9, c = 3
Step-by-step explanation:
Replacing x, y values of the points in the equation y = a*x^2 + b*x +c give the following:
(-1,14)
14 = a*(-1)^2 + b*(-1) + c
(2,-7)
-7 = a*2^2 + b*2 + c
(5, 8)
8 = a*5^2 + b*5 + c
Rearranging:
a - b + c = 14
4*a + 2*b + c = -7
25*a + 5*b + c = 8
This is a linear system of equations with 3 equations and 3 unknows. In matrix notation the system is A*x = b whith:
A =
1 -1 1
4 2 1
25 5 1
x =
a
b
c
b =
14
-7
8
Solving A*x = b gives x = Inv(A)*b, where Inv(A) is the inverse matrix of A. From calculation software (I used Excel) you get:
inv(A) =
0.055555556 -0.111111111 0.055555556
-0.388888889 0.444444444 -0.055555556
0.555555556 0.555555556 -0.111111111
inv(A)*b
2
-9
3
So, a = 2, b = -9, c = 3