Answer:
See proof below.
Step-by-step explanation:
If we assume the following linear model:
And if we have n sets of paired observations 
the model can be written like this:
And using the least squares procedure gives to us the following least squares estimates 
for 
and 
for 
:
Where:
Then 
is a random variable and the estimated value is 
. We can express this estimator like this:
Where 
and if we see careful we notice that 
and 
So then when we find the expected value we got:
And as we can see is an unbiased estimator for
In order to find the variance for the estimator we have this:
And we can assume that 
since the observations are assumed independent, then we have this:
And if we simplify we got:
And with this we complete the proof required.
When
the ball is in the ground, its height is basically equal to zero thus making
our equation,
<span> -16t^2 + 272t + 1344 = 0</span>
Simplifying
the equation will give us,
<span> - t^2 + 17t + 84 = 0 or t^2 – 17t – 84 = 0</span>
Factoring
out the equation will give us,
<span> (t – 21)(t + 4) = 0</span>
Thus,
t = 21 or t = -4. -4 is an extraneous root. Thus, the answer is t = 21.
<span>Answer:
21 seconds</span>
It will be close to 15 days but don’t take my word for it
Answer:
r=(a/b)-1
Step-by-step explanation:
a=b(1+r)
a/b = 1+r
r=(a/b)-1
