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3 years ago

Plz help with this I would mean a lot...Thanks!

Mathematics

2 answers:

jeyben [28]3 years ago

6 0

Answer:

the number is one

Step-by-step explanation:

7-1= 6

6-3=2

hope this help and could u give me brainliest, thanks!

Lady_Fox [76]3 years ago

3 0

Introduction (Kinda)

So you want to write the equation and find the number.

Writing the Equation

Well, the question says "A number s is subtracted from seven. When the result is divided by three, the quotient is two."

If a number s is being subtracted from seven.

7-s

When the result of 7-s is divided by three, the quotient is two. Since your effecting the result of 7-s, you have to put those in parentheses.

(7-s)

Your dividing 7-s by 3.

(7-s) / 3

When you do that, you get 2.

(7-s) / 3 = 2

This is the equation.

Finding the Number

Now you need to solve the equation.

(7-s) / 3 = 2

You need to isolate the s. "Remove" the numbers in opposite PEMDAS order...

Addition and Subtraction

Multiplication and Division

Exponents

Parentheses

7-s is in parentheses.

Divided by 3 is division. So you do that first.

You can multiply by 3 to cancel that out.

(7-s) / 3 × 3 = (7-s)

2 × 3 = 6

7-s = 6

Now that 7-s is on its own side, you can remove the parentheses.

So now to cancel the 7, you subtract 7 from each side (of the equation).

7-s-7 = -s

6-7 = -1

-s = -1

Now to cancel the negative signs, multiply each side by -1.

-s × -1 = s

-1 × -1 = 1

s = 1

Final Answer

The equation is...

(7-s) / 3 = 2

The number is...

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Shards of clay vessels were put together to reconstruct rim diameters of the original ceramic vessels found at the Wind Mountain

Otrada [13]

Answer:

a) In order to calculate the mean and the sample deviation we can use the following formulas:

$\bar X= \sum_{i=1}^n \frac{x_i}{n}$ (2)

$s=\sqrt{\frac{\sum_{i=1}^n (x_i-\bar X)^2}{n-1}}$ (3)

The mean calculated for this case is

The sample deviation calculated $s=3.46 \approx 3.5$

b) $15.8-1.383\frac{3.5}{\sqrt{10}}=14.27$

$15.8+1.383\frac{3.5}{\sqrt{10}}=17.33$

So on this case the 80% confidence interval would be given by (14.27;17.33)

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

Part a

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

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

In order to calculate the mean and the sample deviation we can use the following formulas:

$\bar X= \sum_{i=1}^n \frac{x_i}{n}$ (2)

$s=\sqrt{\frac{\sum_{i=1}^n (x_i-\bar X)^2}{n-1}}$ (3)

The mean calculated for this case is

The sample deviation calculated $s=3.46 \approx 3.5$

Part b

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=10-1=9$

Since the Confidence is 0.80 or 80%, the value of $\alpha=0.2$ and $\alpha/2 =0.1$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.1,9)".And we see that $t_{\alpha/2}=1.383$