Answer:
CI = (70.861 , 94.418)
Step-by-step explanation:
In order to determine the 90% confidence interval you use the following formula (for a population approximately normal):
(1)
: mean = 82.64
σ: standard deviation = 14.32
n: sample = 4
α: tail area = 1 - 0.9 = 0.1
Z_α/2 = Z_0.05: Z factor = 1.645
You replace these values and you obtain:

The confidence interval will be:

The 90% confidence interval is (70.861 , 94.418)
Answer:
It 13
Step-by-step explanation:
Answer:
x=8 ???
Step-by-step explanation:
??? not 100% sure but im pretty sure ;w;
Answer:
is an even function.
Step-by-step explanation:
Recall when it means when a function is even or odd. An even function has the following property:

And an odd function has the following property:

So, let's test some values for cos(x).
Let's use π/3:

From the unit circle, was can see that this is 1/2 (refer to the x-coordinate).
Now, let's find -π/3. This is the same as 5π/3. Thus:

And again from the unit circle, we can see that this is 1/2.
Therefore, despite the negative, the function outputs the same value.
Cosine is an even function.
Notes:
Cosine is an even function and sine is an odd function. It's helpful to remember these as they can help you solve some trig problems!