Find thevmissing value. please

Suppose that a researcher is designing a survey to estimate the proportion of adults in your state who oppose a proposed law tha

irinina [24]

Answer:

$n=\frac{0.5 (1-0.5)}{(\frac{0.02}{1.96})^2}= 2401$

So without prior estimation for the population proportion, using a confidence level of 95% if we want a margin of error about 2% we need al least a sample size of 2401.

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{\hat p(1-\hat p)}{n}})$

Solution to the problem

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

If solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

The margin of error desired for this case is $ME= \pm 0.02$ equivalent to 2% points

For this case we need to assume a confidence level, let's assume 95%. And since we don't have prior estimation for the population proportion of interest the best value to do an approximation is $\hat p =0.5$

In order to find the critical value we need to take in count that we are finding the margin of error for a proportion, so on this case we need to use the z distribution. Since our interval is at 95% of confidence, our significance level would be given by $\alpha=1-0.95=0.05$ and $\alpha/2 =0.025$ . And the critical value would be given by:

$z_{\alpha/2}=\pm 1.96$

Now we have all the values needed and if we replace into equation (b) we got:

$n=\frac{0.5 (1-0.5)}{(\frac{0.02}{1.96})^2}= 2401$

So without prior estimation for the population proportion, using a confidence level of 95% if we want a margin of error about 2% we need al least a sample size of 2401.

5 0

3 years ago

One ballispicked at random from a box containing 3redballs and 1green balls. If X is the number of redballs picked, find the pro

Paladinen [302]

Answer:

P(X = 0) = 0.25

P(X = 1) = 0.75

Step-by-step explanation:

A probability is the number of desired outcomes divided by the number of total outcomes.

The probability distribution of X.

3 red balls out of 4, one picked, so we can have either 0 red balls or 1 red ball. The probability disitribution is the probability of each outcome.

$P(X = 0) = \frac{1}{4} = 0.25$

$P(X = 1) = \frac{3}{4} = 0.75$

6 0

3 years ago

7x + 2y = 24<br>8x + 2y = 30

bagirrra123 [75]

(8x + 2y) - (7x + 2y) = 30 - 24

X = 6

5 0

3 years ago

Read 2 more answers

Identify which statement about the mean of a discrete random variable is not true or state that they are all true.Choose the cor

pashok25 [27]

Answer:

A, C are true . B is not true.

Step-by-step explanation:

Mean of a discrete random variable can be interpreted as the average outcome if the experiment is repeated many times. Expected value or average of the distribution is analogous to mean of the distribution.

The mean can be found using summation from nothing to nothing x times Upper P (x) , i.e ∑x•P(x).

Example : If two outcomes 100 & 50 occur with probabilities 0.5 each. Expected value (Average) (Mean) : ∑x•P(x) = (0.5)(100) + (0.5)(50) = 50 + 25 = 75

The mean may not be a possible value of the random variable.

Example : Mean of possible no.s on a die = ( 1 + 2 + 3 + 4 + 5 + 6 ) / 6 = 21/6 = 3.5, which is not a possible value of the random variable 'no. on a die'

4 0

3 years ago

What is 6x – 1 = 8x + 1

Debora [2.8K]

Answer:

x= -1

Step-by-step explanation:

that's just how it be sometimes?

4 0

3 years ago

Read 2 more answers