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:
14/6
Step-by-step explanation:
I need help to solve this problems can somebody help me
First we are going to find the common denominator of both fractions. To do that, we are going to multiply their denominators:

Now we can rewrite our expression using the common denominator:

Finally, we can use the trig identities:

and

to simplify our trig expression:
We can conclude that the correct answer is the fourth one.