Answer:

Step-by-step explanation:
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
In order to find the critical value we need to take in count that we are finding the critical value for the population mean and without the standard deviation, so on this case we need to use the t distribution. Since our interval is at 95% of confidence, our significance level would be given by
and
. We need to calculate the degrees of freedom are given by:

We can find the critical value using the following excel codes:
"=T.INV(0.025;38)" or "T.INV(1-0.025;38)"
And the critical values would be given by:

<em>what is 5cd when c = 3 and d = 4</em>
<em>put</em><em> </em><em>the</em><em> </em><em>value</em><em> </em><em>c</em><em>=</em><em>3</em><em> </em><em>and</em><em> </em><em>d</em><em>=</em><em>4</em><em> </em><em>then</em><em>,</em>
<em>5</em><em>cd</em><em>=</em><em> </em><em>5</em><em> </em><em>×</em><em> </em><em>3</em><em> </em><em>×</em><em> </em><em>4</em>
<em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em>=</em><em> </em><em>6</em><em>0</em><em> </em>
<em>thus</em><em> </em><em>,</em><em> </em><em>6</em><em>0</em><em> </em><em>is</em><em> </em><em>the</em><em> </em><em>required</em><em> </em><em>answer</em><em>.</em><em>.</em><em>.</em><em>.</em><em>.</em><em>.</em><em>.</em><em>.</em><em>.</em><em>.</em>
The denominator of the second fraction is the difference of squares, so can be factored using the formula for that.
(n^2 -4) = (n -2)(n +2)
Now, you will note that the second fraction has a numerator that is equal to one of the factors in the denominator. In other words, the whole fraction can be simplified to ...
(n +2)/((n +2)(n -2)) = 1/(n -2) . . . . with the restriction n≠-2
This reduced form of the fraction has the same denominator as the first fraction, so you can say that the lowest common denominator is that: (n -2).
_____
If there is some reason you don't want to reduce the second fraction, the lowest common denominator will be (n -2)(n +2).
It’s answer D.
A trinomial is a polynomial with 3 term, and D is the only one with 3 terms :)
Hi I got the answer I will send you soon