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1 year ago

What is the answer to this and show the work please.

Mathematics

1 answer:

Gre4nikov [31]1 year ago

3 0

Which method? There is the substitution method, elimination method, and comparison method

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Multiple choice/ please help!!!

Oxana [17]

Answer:

All are right answer

But one is not (C)

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2 years ago

Please help first person to answer correctly gets 50 and marked as brainly

jeka94

Answer:

HOPE THIS HELPS!!

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1 year ago

The USA Today reports that the average expenditure on Valentine's Day is $100.89. Do male and female consumers differ in the amo

Aloiza [94]

Answer:

$a)\ \ \bar x_m-\bar x_f=67.03\\\\b)\ \ E=15.7416\\\\c)\ \ CI=[51.2884, \ 82.7716]$

Step-by-step explanation:

a. -Given that:

$n_m=41\ , \ \sigma_m=33, \bar x_m=135.67\\\\n_f=37. \ \ ,\sigma_f=20, \ \ \bar x_f=68.64$

#The point estimator of the difference between the population mean expenditure for males and the population mean expenditure for females is calculated as:

$\bar x_m-\bar x_f\\\\\therefore \bigtriangleup\bar x=135.67-68.64\\\\=67.03$

Hence, the pointer is estimator 67.03

b. The standard error of the point estimator, $\bar x_m-\bar x_f$ is calculated by the following following:

$\sigma_{\bar x_m-\bar x_f}=\sqrt{\frac{\sigma_m^2}{n_m}+\frac{\sigma_f^2}{n_f}}$

-And the margin of error, E at a 99% confidence can be calculated as:

$E=z_{\alpha/2}\times \sigma_{\bar x_m-\bar x_f}\\\\\\=z_{0.005}\times\sqrt{\frac{\sigma_m^2}{n_m}+\frac{\sigma_f^2}{n_f}}\\\\\\=2.575\times \sqrt{\frac{33^2}{41}+\frac{20^2}{37}}\\\\\\=15.7416$

Hence, the margin of error is 15.7416

c. The estimator confidence interval is calculated using the following formula:

$\bar x_m-\bar x_f\ \pm z_{\alpha/2}\sqrt{\frac{\sigma_m^2}{n_m}+\frac{\sigma_f^2}{n_f}}$

#We substitute to solve for the confidence interval using the standard deviation and sample size values in a above:

$CI=\bar x_m-\bar x_f\ \pm z_{\alpha/2}\sqrt{\frac{\sigma_m^2}{n_m}+\frac{\sigma_f^2}{n_f}}\\\\=(135.67-68.64)\pm 15.7416\\\\=67.03\pm 15.7416\\\\=[51.2884, \ 82.7716]$

Hence, the 99% confidence interval is [51.2884,82.7716]

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2 years ago

Shelby buys a balance beam priced at $735.40.If the sales tax is

amm1812

Answer:

the sales tax is $73.54

Step-by-step explanation:

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2 years ago

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An online clothing company sells custom sweatshirts. The company charges $4.99 for shipping plus $20 for each sweatshirt. Writ

kap26 [50]

Answer:

20x+4.99=y

Step-by-step explanation:

Each sweatshirt cost $20, but we don't know how many sweatshirts someone will buy so we use X, representing the amount of sweatshirts. There is a shipping charge of $4.99, so we have to add that to the cost of the sweatshirts. 20x+4.99. Y is the total cost.

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2 years ago