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3 years ago

EXPERTs/ACE/GENIUS/TRUSTED HELPERs QUICK!!

Mathematics

1 answer:

Pavel [41]3 years ago

5 0

X 0 y was 30

at x 12 y is about 55

12-0 = 12

55-30 = 25

25/12 = 2.08 inches per year average

so answer should be D

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In a survey, the planning value for the population proportion is p* = 0.35. How large a sample should be taken to provide a 95%

lions [1.4K]

Answer:

$n=\frac{0.35(1-0.35)}{(\frac{0.05}{1.96})^2}=349.59$

And rounded up we have that n=350

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".

$p$ represent the real population proportion of interest

$\aht p$ represent the estimated proportion for the sample

n is the sample size required (variable of interest)

$z$ represent the critical value for the margin of error

Solution to the problem

The population proportion have the following distribution

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

In order to find the critical value we need to take in count that we are finding the interval 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:

$z_{\alpha/2}=-1.96, z_{1-\alpha/2}=1.96$

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)

And on this case we have that $ME =\pm 0.05$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

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

And replacing into equation (b) the values from part a we got:

$n=\frac{0.35(1-0.35)}{(\frac{0.05}{1.96})^2}=349.59$

And rounded up we have that n=350

6 0

3 years ago

200/40+15 = ??<br><br><br>helpp mee ^^

wel

Answer:20 ^v^ Please follow me

Step-by-step explanation:

200/40=5

5+15=20

5 0

3 years ago

Read 2 more answers

A 1-pound box of candy cost $4.00. What was the cost<br> per ounce (1 pound 16 ounces)?

vodka [1.7K]

Answer:

I think its $1 every 4 oz

Step-by-step explanation:

Basing this off that 4 * 4 is 16

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3 years ago

Twice a number increased by 2 is zero

Dmitry_Shevchenko [17]

Alright, so 2x+2=0 (with x being the number) is what I'm getting from this. Subtract 2 from both sides to get 2x=-2, and then divide by 2 to get x=-1

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3 years ago

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Answer the question for a normal random variable x with mean μ and standard deviation σ specified below. (Round your answer to o

vladimir2022 [97]

Answer:

x = 63.6

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X and also the area to its left. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X, which is the area to its right.

In this problem, we have that:

$\mu = 38, \sigma = 11$