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pychu [463]
3 years ago
9

Someone help and please make sure the answer is right :)

Mathematics
1 answer:
Goryan [66]3 years ago
8 0
I got x= -7. hope that helps you out!
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The TreeDropp’d Fruit Company wants to sell its apples overseas in attractive pink and yellow gift boxes. To design the boxes, t
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Answer:

a)For this case the best estimator for the true mean is the sample mean \hat \mu =\bar X because:

E(\bar X)= \frac{\sum_{i=1}^n E(X_i)}{n}

And if we assume that each observation X_1 , X_2,...,X_n follows a normal distribution X_i \sim N(\mu,\sigma) then we have:

E(\bar X)=\frac{1}{n} n\mu =\mu

So then yes the \bar X[/tex[ is a unbiased estimator for the true mean. b) [tex]z_{\alpha/2}=1.96

c) ME= 1.96 \frac{0.4}{\sqrt{50}}=0.1109

Step-by-step explanation:

Previous concepts

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".  

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".

\bar X=4.1 represent the sample mean  

\mu population mean (variable of interest)  

\sigma=0.4 represent the population standard deviation  

n=50 represent the sample size  

Assuming the X follows a normal distribution  

X \sim N(\mu, \sigma=0.4

The sample mean \bar X is distributed on this way:

\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})

A. What is the point estimate in this scenario? Is it an unbiased estimator?

For this case the best estimator for the true mean is the sample mean \hat \mu =\bar X because:

E(\bar X)= \frac{\sum_{i=1}^n E(X_i)}{n}

And if we assume that each observation X_1 , X_2,...,X_n follows a normal distribution X_i \sim N(\mu,\sigma) then we have:

E(\bar X)=\frac{1}{n} n\mu =\mu

So then yes the \bar X[/tex[ is a unbiased estimator for the true mean. B. What is the critical z-value for a 95% interval?
The next step would be find the value of [tex]\z_{\alpha/2}, \alpha=1-0.95=0.05 and \alpha/2=0.025  

Using the normal standard table, excel or a calculator we see that:  

z_{\alpha/2}=1.96

C. What is the margin of error for a 95% interval in this scenario? Show your work.

The margin of error is given by:

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

If we replace the values that we have we got:

ME= 1.96 \frac{0.4}{\sqrt{50}}=0.1109

The confidence interval on this case is given by:

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

Since we have all the values we can replace:

4.1 - 1.96\frac{0.4}{\sqrt{50}}=3.989  

4.1 + 1.96\frac{0.4}{\sqrt{50}}=4.211  

So on this case the 95% confidence interval would be given by (3.989;4.211)  

4 0
3 years ago
An entertainment reporter examines the average ticket prices of Broadway shows, comparing them to the number of total performanc
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Answer: D

Step-by-step explanation: I believe it's D because there's a STRONG, POSITIVE RELATIONSHIP so they're both increasing, but there's no correlation

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Gold in the form of solid cylinders will be molded into solid blocks. Each cylinder has a diameter of 6.19 cm and a height of 6
Taya2010 [7]
First, solve for the volume (V) of each cylinder by the equation,
                                     V = πd²h / 4
where d and h are diameter and height, respectively. Substituting the given values,
                                     V = π(6.19 cm)² x (6 cm) / 4 = 180.56 cm³
To determine the number of cylinders needed, divide the volume of the solid block by the volume of the cylinder,
                                       n = 360 cm³ / 180.56 cm³ = 1.99
Thus, approximately 2 cylinders are needed to mold one block of gold. 
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Answer:Sorry about the sick day.The answer is simply Larry did the greatest.

Step-by-step explanation:First, subtract 54-14=41. Then, you multiply 41 times .25 since 25%=.25.This will give you 10.25.Finally, you subtract 41.00-10.25 to find out the remaining payment from Larry which is 37.50 dollars.Therefore, Larry paid the most.

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She has to add 2 more quarters for 108 more days.

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