To estimate the average education level, in years, of residents in a certain county, a marketing team draws a random sample of 100 residents. Their education level averages to about 12.5 years; the standard deviation is about 2.8 years. The team estimates the average education level of all the residents of that county to be 12.5 years with what margin of error, for approximately 90% confidence?

Answer:

The margin of error is  [tex]E = 0.4606 [/tex]      

Step-by-step explanation:

From the question we are told that

   The sample size is  n = 100

    The sample mean is  [tex]\= x = 12.5 \ years[/tex]

    The standard deviation is  [tex]\sigma = 2.8 \ years[/tex]

From the question we are told the confidence level is  90% , hence the level of significance is    

      [tex]\alpha = (100 - 90 ) \%[/tex]

=>   [tex]\alpha = 0.10[/tex]

Generally from the normal distribution table the critical value  of  [tex]\frac{\alpha }{2}[/tex] is  

   [tex]Z_{\frac{\alpha }{2} } =  1.645[/tex]

Generally the margin of error is mathematically represented as  

      [tex]E = Z_{\frac{\alpha }{2} } *  \frac{\sigma }{\sqrt{n} }[/tex]

=>   [tex]E =1.645*  \frac{ 2.8 }{\sqrt{100} }[/tex]

=>   [tex]E = 0.4606 [/tex]      

Look at these expressions:
3w + 9x - 15y + 7w + 2x + 9y
9x - 8w
6w + 5y + 7x + 4x - 11y + 4w
5x + 9y
3x - 2y + 14w - 4y - 4w + 8x
2y +5w
4w + 5x – y + 6w - 16r - 5y
perimeter =
[4] How many of them are equal?
Do not factorise the answer. Can someone please help me

A taxi cab charges a flat fee of $1.75 plus $0.30 for each half-mile or fraction of a half-mile.

a) Fill in the chart.

b)write and equation for the function.

What’s the answer to this multi step equation? -3(12x+9)=9

if x=3 and x-y= -3

a.4
b.6
c.5
d.10

HEEEEELP PLZ WILL GIVE 30 POINTS!!!!!!!!!!

The ratio of boys to girls in a class is 4: 5
a) What fraction of the class are boys?
b) What fraction of the claşs are girls?

Please help 15 points available! What is the equation of the line that is perpendicular to y - 3 x = 2 and that passes through (6,1)?
y = 1/3x - 1
y = 1/3x + 3
y = -1/3x + 3
y = -1/3x - 1

2.6x0.47pls help
pls pls​

May you please help me on this question ill give out braily

What is the length of z? (Round to the nearest tenth)

What is 56/15 as a decimal rounded to the nearest tenth

X/4-14=9
what is x?

look for a pattern in the first three equations

Seti graphed the point Three-halves and labeled that location P. Which number line shows this point? A number line going from 0 to 2 in increments of 1. There are 2 equals spaces between each number. Point P is half-way between 1 and 2. A number line going from 0 to 2 in increments of 1. There are 3 equal spaces between each number. Point P is on the mark to the left of 1. A number line going from 0 to 2 in increments of 1. There are 2 equals spaces between each number. Point P is half-way between 0 and 1. A number line going from 0 to 2 in increments of 1. There are 3 equal spaces between each number. Point P is on the mark to the right of 1.

Diego says that that the product of 0.51 × 2.427 will have five decimal places. Is Diego correct? Explain.

Evaluate this expression.
112.212 - (- 3.25)

What is the constant
rate of change?
y = 5 – 17x

Please help; I’m stuck on this problem and can’t get past it :(

Find the zero of the function: f(x) = -5x + 5

If I have a black lab, then I have a dog. What is this statement called: if I do not have a dog then I do not have a black lab. HELP PLEASE

A) inverse
B) converse
C) conditional
D) contrapositive

What is the image point of (0, 2) after a translation lett 5 units and down 1 unit?

Katie completes 2/3 of her craft project in 3/4 of an hour at this rate what fraction of the craft project does Katie complete in one hour give your answer in fraction form

It is known that a laptop company's average production is given by P(t) = (150t) / (3t+20), where

t is the time (in days). How many days will it take the company to produce 30 laptops?

Four students took an exam. The
fraction of the total possible points that each
received is given. Which student had the highest
score? If students receive a whole number of
points on every exam item, can the exam be
worth a total of 80 points? Explain.

Please I need some answers

A new sidewalk will be 4 feet​ wide, 240 feet​ long, and filled to a depth of 9 inches ​(0.75 ​foot) with concrete. How many cubic yards of concrete are​ needed?

I NEED HELP WITH THIS PLSS!!!

You reflect triangle PQR, with vertices P(-2, -4), Q(-3, -1), and R(-4, -4), across the y-axis to get triangle P′Q′R′. What are the coordinates of triangle P′Q′R′?

If you can answer this it would help me out so much!
A certain quadratic function has the factors (x + 3) and (2x - 1). What are the solutions of the function?
A- (0,3) and (0, -1)
B- (-1,0) and (3,0)
C- (6,0) and (-3,0)
D- (0,1/2) and (0, -3)

What is the slope of a line that passes through (-4 -13) and (19, 11)
a. 23/24
b. 24/23
c. -23/24
d. -24/23