Answer:
<h2>
$5.03</h2>
Step-by-step explanation:
Given data
Sample Mean (M): $48.77
Sample Size (n): 20
Standard Deviation (σ) : $17.58
Confidence Level: 80%
we know that z*-Values for 80% Confidence Levels is 1.28
the expression for margin of error is given bellow\
MOE= z*σ/√n
We can now substitute into the expression and solve for the MOE as
MOE= 1.28*17.58/√20
MOE= 22.502/4.47
MOE= 22.502/4.47
MOE= 5.03
The margin of error for a 80 % confidence interval is $5.03
(1.5) decimal form (mixed number form= 1/2-1) hope this helps.
You can know a perfect square trinomial:
i) if the coefficient of a² = 1.
ii) If you divide the middle number coefficient by 2 and you square it you get the last term.
Take for example the first option:
For all the options, the coefficient of a² = 1
a² + 4a + 16.
Coefficient of a = 4.
4/2 = 2
2² = 4, this does not equal the last term so it is not a perfect square trinomial.
a² + 14a + 49.
Coefficient of a = 14.
14/2 = 7
7² = 49, this is equal the last term so it is a perfect square trinomial.
And the perfect square is (a +7)²
Similarly if you test the last option.
a² + 26a + 169.
Coefficient of a = 26.
26/2 = 13
13² = 169, this is equal the last term so it is a perfect square trinomial.
And the perfect square is (a +13)²
So the only two options are: a² + 14a + 49 and a² + 26a + 169.
Other options do not pass this test.
