We need to find out how many adults must the brand manager survey in order to be 90% confident that his estimate is within five percentage points of the true population percentage.
From the given data we know that our confidence level is 90%. From Standard Normal Table we know that the critical level at 90% confidence level is 1.645. In other words,
.
We also know that E=5% or E=0.05
Also, since,
is not given, we will assume that
=0.5. This is because, the formula that we use will have
in the expression and that will be maximum only when
=0.5. (For any other value of
, we will get a value less than 0.25. For example if,
is 0.4, then
and thus,
.).
We will now use the formula

We will now substitute all the data that we have and we will get



which can approximated to n=271.
So, the brand manager needs a sample size of 271
Answer:
(-1, 1)
General Formulas and Concepts:
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
Equality Properties
- Multiplication Property of Equality
- Division Property of Equality
- Addition Property of Equality
- Subtraction Property of Equality<u>
</u>
<u>Algebra I</u>
- Terms/Coefficients
- Coordinates (x, y)
- Solving systems of equations using substitution/elimination
Step-by-step explanation:
<u>Step 1: Define Systems</u>
y = 2x + 3
y = x + 2
<u>Step 2: Solve for </u><em><u>x</u></em>
<em>Substitution</em>
- Substitute in <em>y</em>: 2x + 3 = x + 2
- [Subtraction Property of Equality] Subtract <em>x</em> on both sides: x + 3 = 2
- [Subtraction Property of Equality] Subtract 3 on both sides: x = -1
<u>Step 3: Solve for </u><em><u>y</u></em>
- Substitute in <em>x</em> [Original Equation]: y = -1 + 2
- Add: y = 1
Answer:
$57,791.8
Step-by-step explanation:
Each acre cost $43.60.
If the famer wants to harvest 1325.5 acres he has to pay 43.6 per acre
43.60×1325.5= 57,791.8
Answer:
Length = 21
Width = 16
Step-by-step explanation:
We know that the formula for perimeter is:
P=2W+2L
And we also know that:
L=W+5
So then we put all that we know in the formula:
74=2W+2(W+5)
Now we expand the brackets and do some algebra:
74=4W+10 (-10)
64=4W (÷4)
16=W
Now that we know the width we can pop that into the length equation:
L=16+5
L=21