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2 years ago

Can anyone help please ?

Mathematics

1 answer:

expeople1 [14]2 years ago

5 0

Answer:

A) √A/ $\pi$

Step-by-step explanation:

A= $\pi$ r²

A/ $\pi$ =r²

√A/ $\pi$ =r

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(x2y-3y2+5xy2)-(-x2y+3xy2-3y2)

Reil [10]

2x2y+8xy2-6y2 .........

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2 years ago

Sarah needs 10 feet of fabric for a project she is working on, but the store only sells the fabric in meters. One meter of fabri

Aleks [24]

<h2>Hello!</h2>

The answer is:

The fabric will cost $4.58

D.$4.58

Since it's a conversion exercise, we need to pay special attention to the conversion procedure.

From the statement we know that:

$1ft=0.305m$

So, if she needs 10 feet of fabric, we need to convert it to meters, and then, calculate its cost.

We have that:

$10*1ft=10*0.305m\\\\10ft=3.05m$

Now, we have that each meter of fabric cost $1.50, so, 3.05m of fabric will cost:

$\frac{1m}{1.50(dollars)}=\frac{3.05m}{cost}\\\\cost=\frac{3.05m*1.50(dollars)}{1m}=4.575(dollars)=4.58(dollars)$

Hence, we have that the cost of the fabric will be $4.58.

The correct option is: D.$4.58

Have a nice day!

6 0

2 years ago

A simple random sample of 100 observations was taken from a large population. The sample mean and the standard deviation were de

olga2289 [7]

Answer:

Se=1.2

Step-by-step explanation:

The standard error is the standard deviation of a sample population. "It measures the accuracy with which a sample represents a population".

The central limit theorem (CLT) states "that the distribution of sample means approximates a normal distribution, as the sample size becomes larger, assuming that all samples are identical in size, and regardless of the population distribution shape"

The sample mean is defined as:

$\bar X =\frac{\sum_{i=1}^n x_i}{n}$

And the distribution for the sample mean is given by:

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

Let X denotes the random variable that measures the particular characteristic of interest. Let, X1, X2, …, Xn be the values of the random variable for the n units of the sample.

As the sample size is large,(>30) it can be assumed that the distribution is normal. The standard error of the sample mean X bar is given by:

$Se=\frac{\sigma}{\sqrt{n}}$