1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
ELEN [110]
3 years ago
15

A recent survey based on a random sample of n=470 voters, predicted that independent candidate for the mayoral election will get

24% of the vote, but he actually got 27%. discuss whether the claim that suggest the survey was done incorrectly! explain your rational.
Mathematics
1 answer:
julsineya [31]3 years ago
7 0

I have an expression

\sigma = \sqrt{p(1-p)/n}

floating around in my head; let's see if it makes sense.

The variance of binary valued random variable b that comes up 1 with probability p (so has mean p) is

E( (b-p)^2 ) =  (-p)^2(1-p) + (1-p)^2p = p(1-p)

That's for an individual sample. For the observed average we divide by n, and for the standard deviation we take the square root:

\sigma = \sqrt{p(1-p)/n}

Plugging in the numbers,

\sigma = \sqrt{.24(1-.24)/490} = 0.019 = 1.9\%

One standard deviation of the average is almost 2% so a 27% outcome was 3/1.9 = 1.6 standard deviations from the mean, corresponding to a two sided probability of a bit bigger than 10% of happening by chance.

So this is borderline suspect; most surveys will include a two sigma margin of error, say plus or minus 4 percent here, and the results were within those bounds.

You might be interested in
What is 0.0417 in scientific notation?
Lina20 [59]
The scientific  notation: 4.17 x 10^-2
5 0
2 years ago
Read 2 more answers
You plan to conduct a survey to find what proportion of the workforce has two or more jobs. You decide on the 95% confidence lev
Vikentia [17]

Answer:

865

Step-by-step explanation:

We have that in 95% confidence level the value of z has a value of 1.96. This can be confirmed in the attached image of the normal distribution.

Now we have the following formula:

n = [z / E] ^ 2 * (p * q)

where n is the sample size, which is what we want to calculate, "E" is the error that is 2% or 0.02. "p" is the probability they give us, 5 out of 50, is the same as 1 out of 10, that is 0.1. "q" is the complement of p, that is, 1 - 0.1 = 0.9, that is, the value of q is 0.9.

Replacing these values we are left with:

n = [1.96 / 0.02] ^ 2 * [(0.1) * (0.9)]

n = 864.36

865 by rounding to the largest number.

3 0
3 years ago
Please solve the following question!!
Komok [63]
2(21x − 7) + 4(3x + 2) = 6(2x + 9) + 3
42x - 14 + 12x + 8= 12x + 54 + 3
54x - 6= 12x + 57
54x=12x + 63
42x=63
x= 63/42
x= 3/2
4 0
3 years ago
Item 17 The amount of chlorine in a swimming pool varies directly with the volume of water. The pool has 2.5 milligrams of chlor
zvonat [6]
8000 gal *\frac{ 1 L}{0.264 gal}*\frac{2.5 mg}{1 L} = 75,757 mg

Rounding to nearest thousand gives 76,000 mg of chlorine
7 0
3 years ago
What is the area underneath a normal curve always equal to?
Pani-rosa [81]
The correct answer is C. One
3 0
2 years ago
Read 2 more answers
Other questions:
  • What is  8x8x8x7x7=<br>using write with exponents
    5·2 answers
  • It take Anna 45 minutes to walk 2 1/2 miles to the park. At this rate, how many minutes should it take her to walk 3 miles?
    14·1 answer
  • A root of x2 – 5x – 1 = 0 is
    5·2 answers
  • The graph of the inequality will have a dashed line y&gt; 2x -5
    14·2 answers
  • in cooking, 1 drop is equal to 1/6 of a dash. if a recipe calls for 2/3 of a dash, write an expression that would give the numbe
    14·1 answer
  • A bag of marbles has 15 blue, 18 green, 6 yellow, and 10 red marbles. How many marbles need to be added to the bag so the probab
    12·2 answers
  • WILL AWARD BRAINLEST<br><br><br><br><br><br><br> Please show work.
    11·2 answers
  • (-32ux+19u^2x^3-12u^6x^7) divided by (-4u^2x^3)
    15·1 answer
  • At mr.v backyard ranch there are35 chickens and 20 cows what is the ratio of number of cows to the number of chickens
    13·1 answer
  • 100 POINTS AND BRAINILY
    5·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!