Answer:
Now we just take square root on both sides of the interval and we got:
And the best option would be:
A. 2.2 < σ < 2.8
Step-by-step explanation:
Information provided
represent the sample mean
population mean
s=2.4 represent the sample standard deviation
n=83 represent the sample size
Confidence interval
The confidence interval for the population variance is given by the following formula:
The degrees of freedom are given by:
The Confidence is given by 0.90 or 90%, the value of 
and 
, the critical values for this case are:
And replacing into the formula for the interval we got:
Now we just take square root on both sides of the interval and we got:
And the best option would be:
A. 2.2 < σ < 2.8
Pir^2
2pi2
Hope this helps
Answer:
-3 1/3
Step-by-step explanation:
The quadratic
... y = ax² +bx +c
has its extreme value at
... x = -b/(2a)
Since a = 3 is positive, we know the parabola opens upward and the extreme value is a minimum. (We also know that from the problem statement asking us to find the minimum value.) The value of x at the minimum is -(-4)/(2·3) = 2/3.
To find the minimum value, we need to evaluate the function for x=2/3.
The most straightforward way to do this is to substitue 2/3 for x.
... y = 3(2/3)² -4(2/3) -2 = 3(4/9) -8/3 -2
... y = (4 -8 -6)/3 = -10/3
... y = -3 1/3
_____
<em>Confirmation</em>
You can also use a graphing calculator to show you the minimum.
To do this, divide 9 by 5. it is one, with a remainder of 4. so the 4 goes over 5 as a fraction. the answer is then 1 4/5
The square root of 16 is 4
