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.
3.) 2 × 0.5 = 1
4.) -2 × -0.5 = 1
Answer:
After 2 seconds
Step-by-step explanation:
First step is find an equation of velocity:
h(t)=-16t2+64t+112. The velocity function is derivated from position function, so we should do that.
v(t)= h´(t)= -16*2*t+64 ⇒ v(t)= -32t+64.
Now we know the arrow reach the maximun height when this velocity is equal to zero when t>0.
0=-32t+64 ⇒ 32t=64, split each member for 32 ⇒
=
t=2. That means after 2 sec. the arrow reach the maximum height
Answer:
18 stars
Step-by-step explanation:
We can use a ratio to solve
9 stars x
--------- = -----------
2 hearts 4 hearts
Using cross products
9*4 = 2x
36 = 2x
Divide by 2
36/2 =2x/2
18 =x
18 stars