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Diano4ka-milaya [45]
3 years ago
8

You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard devia

tion is approximately σ = 54.5 . You would like to be 99% confident that your estimate is within 5 of the true population mean. How large of a sample size is required
Mathematics
1 answer:
Arturiano [62]3 years ago
4 0

Answer:

n=(\frac{z_{\alpha/2} \sigma}{ME})^2   (3)

n=(\frac{2.58(54.5)}{5})^2 =790.846 \approx 791

So the answer for this case would be n=791 rounded up to the nearest integer

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".

\bar X represent the sample mean for the sample  

\mu population mean (variable of interest)

s represent the sample standard deviation

n represent the sample size  

Solution to the problem

The confidence interval for the mean is given by the following formula:

\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}   (1)

Since the Confidence is 0.99 or 99%, the value of \alpha=0.01 and \alpha/2 =0.005, and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.005,0,1)".And we see that z_{\alpha/2}=2.58

The margin of error is given by this formula:

ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}    (2)

And on this case we have that ME =+5 and we are interested in order to find the value of n, if we solve n from equation (2) we got:

n=(\frac{z_{\alpha/2} \sigma}{ME})^2   (3)

n=(\frac{2.58(54.5)}{5})^2 =790.846 \approx 791

So the answer for this case would be n=791 rounded up to the nearest integer

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Answer: FIRST OPTION.

Step-by-step explanation:

Regular polygons are those polygons whose sides are equal in length and whose angles are all equal.

By definition each interior angle of a Regular polygon,is:

\frac{180 ( n -2 )}{n}  (In degrees)

Where "n" is the number of sides of the polygon.

Observe the Regular polygon given in the exercise.

Since it has 6 sides, you can conclude that it is an Hexagon. Then:

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Knowing this, you can write the following equation:

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3 years ago
Just need help with #6
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Answer:

Step-by-step explanation:

a) The rate of change is referred to as slope

Slope = change in value of y on the vertical axis / change in value of x on the horizontal axis

change in the value of y = y2 - y1

Change in value of x = x2 -x1

From the graph,

y2 = 160 = final value of y

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b) initial height of the biker above the Canyon was 360 feets. It is reducing as the time is increasing.

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d) After 9 minutes, the hiker was 180 feets above the Canyon floor

e) it took 7 minutes for the hiker to reach 220 feets above the Canyon floor.

f) The domain is the set of all possible values of the independent variable and the independent variable is time.

The time between which the hiker was at the maximum height and the minimum height lies between 18 minutes and 0 minutes.

The domain is 0 lesser than or equal to t lesser than or equal to 18.

The range is the set of all possible values of the dependent variable and the dependent variable is height of the hiker above the Canyon. The maximum height of the hiker was 360 feet and the minimum height of the hiker was 0 feet. Let the height be h.

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Answer:

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Step-by-step explanation:

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

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