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jarptica [38.1K]
3 years ago
15

A public opinion poll in Ohio wants to determine whether registered voters in the state approve of a measure to ban smoking in a

ll public areas. The researchers select a simple random sample of 50 registered voters from each county in the state and ask whether they approve or disapprove of the measure. This is an example of A. a systematic county sample. B. a stratified sample. C. a multistage sample. D. a simple random sample.
Mathematics
1 answer:
LUCKY_DIMON [66]3 years ago
8 0

This is an example of "a stratified sample".

<u>Answer:</u> Option B

<u>Explanation:</u>

A group-based sampling process that can be divided into subpopulations. For statistical studies, testing of each subpopulation separately may be useful if subpopulations within a total population differ, thus understood as "Stratified sampling".

One might, for instance, divide a adults sample into subgroups in terms of age, like 18 to 29, 30 to 39, 40 to 49, 50–59 etc with decided age difference as needed. A stratified sample may be more accurate than an easy sample of the similar size by random. As it offers more accuracy, a stratified sample sometimes involves a smaller sample, saving money.

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Find the domain of the function.<br> f(x)= x+2/1-X
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Answer:

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3 0
3 years ago
Does anyone know how to do this?? Help please!!!!
Doss [256]

Answer:

When we have a rational function like:

r(x) = \frac{x + 1}{x^2 + 3}

The domain will be the set of all real numbers, such that the denominator is different than zero.

So the first step is to find the values of x such that the denominator (x^2 + 3) is equal to zero.

Then we need to solve:

x^2 + 3 = 0

x^2 = -3

x = √(-3)

This is the square root of a negative number, then this is a complex number.

This means that there is no real number such that x^2 + 3 is equal to zero, then if x can only be a real number, we will never have the denominator equal to zero, so the domain will be the set of all real numbers.

D: x ∈ R.

b) we want to find two different numbers x such that:

r(x) = 1/4

Then we need to solve:

\frac{1}{4} = \frac{x + 1}{x^2 + 3}

We can multiply both sides by (x^2 + 3)

\frac{1}{4}*(x^2 + 3) = \frac{x + 1}{x^2 + 3}*(x^2 + 3)

\frac{x^2 + 3}{4} = x + 1

Now we can multiply both sides by 4:

\frac{x^2 + 3}{4}*4 = (x + 1)*4

x^2 + 3 = 4*x + 4

Now we only need to solve the quadratic equation:

x^2 + 3 - 4*x - 4 = 0

x^2 - 4*x - 1 = 0

We can use the Bhaskara's formula to solve this, remember that for an equation like:

a*x^2 + b*x + c = 0

the solutions are:

x = \frac{-b +- \sqrt{b^2 - 4*a*c} }{2*a}

here we have:

a = 1

b = -4

c = -1

Then in this case the solutions are:

x = \frac{-(-4) +- \sqrt{(-4)^2 - 4*1*(-1)} }{2*(1)} = \frac{4 +- 4.47}{2}

x = (4 + 4.47)/2 = 4.235

x = (4 - 4.47)/2 = -0.235

5 0
3 years ago
In a survey of 603 adults, 98 said that they regularly lie to people conducting surveys. Create a 99% confidence interval for th
marysya [2.9K]

Answer:

The population proportion is estimated to be with 99% confidence within the interval (0.1238, 0.2012).

Step-by-step explanation:

The formula for estimating the population proportion by a confidence interval is given by:

\hat{p}\pm z_{\alpha /2}\times\sqrt{\frac{\hat{p}\times(1-\hat{p})}{n}}

Where:

\hat{p} is the sample's proportion of success, which in this case is the people that regularly lie during surveys,

z_{\alpha /2} is the critical value needed to find the tails of distribution related to the confidence level,

n is the sample's size.

<u>First</u> we compute the \hat{p} value:

\hat{p}=\frac{successes}{n}=\frac{98}{603}=0.1625

<u>Next</u> we find the z-score at any z-distribution table or app (in this case i've used StatKey):

z_{\alpha /2}=2.576

Now we can replace in the formula with the obtained values to compute the confidence interval:

\hat{p}\pm z_{\alpha /2}\times\sqrt{\frac{\hat{p}\times(1-\hat{p})}{n}}=0.1625\pm 2.576\times\sqrt{\frac{0.1625\times(1-0.1625)}{603}}=(0.1238, 0.2012)

5 0
3 years ago
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