Answer:
b. 224
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
.
So it is z with a pvalue of 
, so 
Now, find the margin of error M as such
In which 
is the standard deviation of the population and n is the size of the sample.
In this problem:
We want to find n, when 
So
The nearest integer number to 223.9 is 224.
So the correct answer is:
b. 224
A is the answer
divide 0.5/ 0.1
Answer:
3.
Step-by-step explanation:
3(n + 4) = 21
3n + 12 = 21
3n = 21 - 12 = 9
n = 3.
Answer:
- <em>B. The grouping method of factoring trinomials involves rewriting the bx term into the factors that fit the particular trinomial, and factoring these four terms using grouping</em>
Explanation:
The description may be better explained by applying it to an example.
Example:
- the general form of a trinomial is a x² - bx - 30
- comparing with x² - x - 30 the <em>bx term </em>is - x
- then you must <em>rewrite the bx term, - x,</em> into two terms whose coefficients are factors of 30:
Two numbers which add up - 1 and multipled are - 30. Those numbers are - 6 and + 5, because -6 + 5 = - 1 and (-6) × (+5) = -30.
Hence, the two terms are -6x and 5x, and the expression rewritten is:
x² - 6x + 5x - 30
- <em>factor these four terms using grouping</em>:
(x² - 6x) + (5x - 30)
x(x - 6) + 5(x - 6)
(x - 6) (x + 5)
Hence, the factored trinomial is (x - 6) (x + 5)
