Ask question

Ask question

All categories

3 years ago

14

STATISTICS Statisticians use the formula σ = √v to calculate a standard deviation σ, where v is the variance of a data set. Find

the variance when the standard deviation is 15.

1 answer:

Leokris [45]3 years ago

3 0

If <span>σ = the standard deviation and we know the deviation is 15 we can set his up like the following:

</span><span>σ = √v
</span><span>15 = √v
Square both sides:
$15^2 = \sqrt{v}^2$
</span> $225 = v$
$v = 225$

You might be interested in

Suppose you estimated square root of 12 by averaging a square like rectngle.What would be a reasonable estimation?

sesenic [268]

Answer:

3.5.

Step-by-step explanation:

3^2 = 9

and 4^2 = 16 so the square root is between 3 and 4.

Take a rectangle 3.4 by 3.6:

the area = 3.4 * 3.6 = 12.24 so an estimate of the square root could be 3.5.

3.5 * 3.5 = 12.25.

5 0

3 years ago

Cynthia besch wants to buy a rug for a room that is 23ft wide and 26ft long. She wants t ok leave a uniform strip of floor aroun

Lostsunrise [7]

Answer:

Dimension of rug is $(15\times 18)\ ft$

Step-by-step explanation:

Given: Area of rug= 270 ft²

Cynthia besch wants to buy a rug for a room that is 23ft wide and 26ft long.

Let´s assume the uniform strip size of floor around rug be "x".

As given, Cynthia wants to leave a uniform strip of floor around the rug.

∴ Rug dimension will be $(23-2x)\times (26-2x)$

We know, area of rectangle= $width\times length$

Forming an equation for area of rug.

⇒ $270= (23-2x)\times (26-2x)$

Now solving the equation to find the dimension of rug.

$270= (23-2x)\times (26-2x)$

Using distributive property of multiplication.

⇒ $270= 598-46x-52x+4x^{2}$

⇒ $598-98x+4x^{2}= 270$

Subtracting both side by 270

⇒ $4x^{2}-98x+328= 0$

using quadratic formula to solve the equation.

⇒ Formula: $\frac{-b\pm \sqrt{b^{2}-4(ac) } }{2a}$

∴ In the expression , we have a= 4, b= -98 and c= 328.

Now, subtituting the value in the formula.

= $\frac{-(-98)\pm \sqrt{-98^{2}-4(4\times 328) } }{2\times 4}$

= $\frac{98\pm \sqrt{9604-4(1312) } }{8}$

Opening parenthesis.

= $\frac{98\pm \sqrt{9604-5248 } }{8}$

= \frac{98\pm \sqrt{4356}}{8}

We know 66²=4356 and √a²=a or -a

= $\frac{98\pm 66}{8}$

= $\frac{98+66}{8}\ or \ \frac{98-66}{8}$

= $20.5 \ or\ 4$

∴ Value of x will be either 20.5 ft or 4 ft

Ignoring decimal value, therefore taking value of x is 4 ft

Subtituting the value of x to find the dimension of rug.

Width of rug= $(23-2x)$

⇒ Width of rug= $23- 2\times 4$

⇒ Width of rug= $23-8= 15\ ft$

Next, Length of rug= $(26-2x)$

⇒ Length of rug= $(26-2\times 4)$

⇒ Length of rug= $26-8= 18\ ft$

Hence, dimension of rug is $(15\times 18)\ ft$

6 0

3 years ago

The length of segment EF is 8 units, the length of segment ED is 10 units, and the length of segment EA is 13.33 units. Find the

ivanzaharov [21]

Answer:

5.33 unit

Step-by-step explanation:

logically FA = EA - EF = 13.33-8 = 5.33 units

Since, E, F and A all lie on the same line EA . The information ED= units is redundant. Therefore we can say that FA= 5.33 unit

5 0

3 years ago

The lettwrs a e i o u and y are vowels. if one letter of alphabet is chosen at random what is the probability it is a vowel

SashulF [63]

The probability is 6/26

7 0

4 years ago

Read 2 more answers

un grupo de 247 personas viajan en camionetas del zoológico.el mayor numero de personas que pueden viaja es 15 cuel es el menor

Cloud [144]

Answer: 17

Step-by-step explanation:

:)

4 0

3 years ago