Evaluate the function. f(x) = -x2 + 5x + 15 Find f(9)
2 answers:
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Answer:
0.125 seconds.
Step-by-step explanation:
We have been given that the height of a ball above the ground as a function of time is given by the function , where h is the height of the ball in feet and t is the time in seconds.
We can see that our given equation is a downward opening parabola as its leading coefficient is negative. The maximum point will be vertex of parabola.
To find the time, when the ball would be at its maximum height, we need to find the x-coordinate of vertex.
Using formula , we will find the x-coordinate of vertex of parabola as:
Therefore, the ball will be at a maximum height after 0.125 seconds.
Answer:
a) the sample size is 400
b) 95% confidence Interval for p is ( 0.0286, 0.0714 )
Step-by-step explanation:
Given the data in the question;
sample size n = 400
x = 20
p = x / n = 20 / 400 = 0.05
q = 1 - p = 1 - 0.05 = 0.95
a)
n = 400
Hence, the sample size is 400
b) 95% confidence Interval for p;
At 95% confidence interval,
significance level ∝ = 1 - 95% = 1 - 0.95 = 0.05
∝/2 = 0.05 / 2 = 0.025
so, Z critical Value ; = 1.96 { from table }
So for Confidence Interval for p;
⇒ p' ± √( p'q' / n )
we substitute
⇒ 0.05 ± 1.96√( (0.05 × 0.95 ) / 400 )
⇒ 0.05 ± 1.96√( 0.00011875 )
⇒ 0.05 ± 1.96 × 0.010897
⇒ 0.05 ± 0.021358
⇒ ( 0.05 - 0.021358 ), ( 0.05 + 0.021358 )
⇒ ( 0.0286, 0.0714 )
Therefore, 95% confidence Interval for p is ( 0.0286, 0.0714 )