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:
Slope <em>m</em> = -5/4
y-intercept <em>b</em> = 3
General Formulas and Concepts:
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
<u>Algebra I</u>
Equality Properties
Slope-Intercept Form: y = mx + b
- m - slope
- b - y-intercept
Step-by-step explanation:
<u>Step 1: Define</u>
[Standard Form] -5x - 4y = -12
<u>Step 2: Rewrite</u>
- Add 5x to both sides: -4y = 5x - 12
- Divide -4 on both sides: y = -5/4x + 3
<u>Step 3: Identify</u>
<em>Break apart the function.</em>
Slope <em>m</em> = -5/4
y-intercept <em>b</em> = 3
Answer:
the player will win
Step-by-step explanation:
the team wont win
Answer:
Answer in the photo
Step-by-step explanation:
Just simplify the expression
Answer:
30 gallons of 20% acid solution should be mixed.
Step-by-step explanation:
Let x gallons of a 20% acid solution was mixed with 30 gallons of a 40% solution, to obtain a mixture of 30% acid solution.
Therefore, final volume of the solution will be (x + 30) gallons.
Now concept to solve this question is
20%.(x) + 40%.(30) = 30%.(x + 30)
0.20(x) + 0.40(30) = 0.30(x + 30)
0.20x + 12 = 0.30x + 9
0.30x - 0.20x = 12 - 9
.10x = 3
x = 
x = 30 gallons
Therefore, 30 gallons of the 20% acid solution should be mixed.