Answer: 
Step-by-step explanation:
The confidence interval for population mean is given by :-
Given : Sample size : 
, which is a large sample , so we apply z-test .
Sample mean : 
Standard deviation : 
Significance level : 
Critical value : 
Now, a confidence interval at the 95% level of confidence will be :-
<h3>
Answer: b = 4 and c = 7.</h3>
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Explanation:
Comparing y = x^2+bx+c to y = ax^2+bx+c, we see that a = 1.
The vertex given is (-2,3). In general, the vertex is (h,k). So h = -2 and k = 3.
Plug those three values into the vertex form below
y = a(x-h)^2 + k
y = 1(x-(-2))^2 + 3
y = (x+2)^2 + 3
Then expand everything out and simplify
y = x^2+4x+4 + 3
y = x^2+4x+7
We see that b = 4 and c = 7.
Volume for a cone is 1/3 pi * r^2*h, where r is radius and h is height. We have diameter = 1/2 radius. Thus, radius = 1.5in. We also have volume is 12 in. Using formula for volume of a cone and plugging in what we know, we have 12 = 1/3*pi*(1.5)^2*h, were solving for h. To get, h= (12*3)/(pi*(1.5)^2), which is approximately 5.0931in, 5 inches
