Answer:
Part 1) The graphs open downward
Part 2) The vertex is the point (-2,5)
Part 3) The axis of symmetry is x=-2
Step-by-step explanation:
step 1
we have
This is a vertical parabola open downward (because the leading coefficient is negative)
The vertex is a maximum
step 2
The quadratic equation is written in vertex form
where
(h,k) is the vertex
so
In this problem
The vertex is the point (-2,5)
step 3
The equation of the axis of symmetry of a vertical parabola is equal to the x-coordinate of the vertex
The x-coordinate of the vertex is -2
therefore
The axis of symmetry is x=-2
Given:
μ = 25 mpg, the population mean
σ = 2 mpg, the population standard deviation
If we select n samples for evaluation, we should calculate z-scores that are based on the standard error of the mean.
That is,
The random variable is x = 24 mpg.
Part (i): n = 1
σ/√n = 2
z = (24 -25)/2 = -0.5
From standard tables,
P(x < 24) = 0.3085
Part (ii): n = 4
σ/√n = 1
z = (24 -25)/1 = -1
P(x < 24) = 0.1587
Part (iii): n=16
σ/√n = 0.5
z = (24 - 25)/0.5 = -2
P(x < 24) = 0.0228
Explanation:
The larger the sample size, the smaller the standard deviation.
Therefore when n increases, we are getting a result which is closer to that of the true mean.
I think the answer is b but I am not quite sure
16-4(3+2:2)
16-4(3+1)
16-4 x 4
16-16=0
calculate rise over run = 37 ÷ 63
