Answer:
A sample of 18 is required.
Step-by-step explanation:
We have that to find our
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Z-table as such z has a p-value of
.
That is z with a pvalue of
, so Z = 1.88.
Now, find the margin of error M as such
In which
is the standard deviation of the population and n is the size of the sample.
A previous study indicated that the standard deviation was 2.2 days.
This means that 
How large a sample must be selected if the company wants to be 92% confident that the true mean differs from the sample mean by no more than 1 day?
This is n for which M = 1. So



Rounding up:
A sample of 18 is required.
The answer is: (z - 6)(z + 15)
z² + 9z - 90 = z*z + 15z - 6z - 6*15 =
= (z*z + 15z) - (6z + 6*15) =
= z(z + 15) - 6(z + 15) =
= (z - 6)(z + 15)
Answer:
y=1
Step-by-step explanation:
Step 1: Simplify both sides of the equation.
6=2(y+2)
6=(2)(y)+(2)(2)(Distribute)
6=2y+4
Step 2: Flip the equation.
2y+4=6
Step 3: Subtract 4 from both sides.
2y+4−4=6−4
2y=2
Step 4: Divide both sides by 2.
2y/2 2/2
9514 1404 393
Answer:
(x, y) = (5, -4)
Step-by-step explanation:
The Desmos graphing calculator is a handy tool for solving questions like this one. It tells you the solution is ...
(x, y) = (5, -4)