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2 years ago

10

Need help plz very difficult

1 answer:

Oksanka [162]2 years ago

6 0

Answer:

D - 9x^(2)+2x-5

Step-by-step explanation:

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Set A of six numbers has a standard deviation of 3 and set B of four numbers has a standard deviation of 5. Both sets of numbers

Alenkinab [10]

Given:

$\sigma_A=3$

$n_A=6$

$\sigma_B=5$

$n_B=4$

$\overline{x}_A=\overline{x}_B$

To find:

The variance. of combined set.

Solution:

Formula for variance is

$\sigma^2=\dfrac{\sum (x_i-\overline{x})^2}{n}$ ...(i)

Using (i), we get

$\sigma_A^2=\dfrac{\sum (x_i-\overline{x}_A)^2}{n_A}$

$(3)^2=\dfrac{\sum (x_i-\overline{x}_A)^2}{6}$

$9=\dfrac{\sum (x_i-\overline{x}_A)^2}{6}$

$54=\sum (x_i-\overline{x}_A)^2$

Similarly,

$\sigma_B^2=\dfrac{\sum (x_i-\overline{x}_B)^2}{n_B}$

$(5)^2=\dfrac{\sum (x_i-\overline{x}_B)^2}{4}$

$25=\dfrac{\sum (x_i-\overline{x}_B)^2}{4}$

$100=\sum (x_i-\overline{x}_B)^2$

Now, after combining both sets, we get

$\sigma^2=\dfrac{\sum (x_i-\overline{x}_A)^2+\sum (x_i-\overline{x}_B)^2}{n_A+n_B}$

$\sigma^2=\dfrac{54+100}{6+4}$

$\sigma^2=\dfrac{154}{10}$

$\sigma^2=15.4$

Therefore, the variance of combined set is 15.4.

7 0

2 years ago

Look at this set of 8 numbers:33769234 how would the range change if the number 6 replaced the number 7 in the set

klio [65]

Put the numbers in order

2,3,3,3,4,6,7,9.....the range is the largest number minus the smallest number
so as it is, the range is (9 - 2) = 7

if u replaced the 7 with a 6...
2,3,3,3,4,6,6,9...the range is STILL (9 - 2) = 7

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2 years ago

Sophia downloaded 592 vacation pictures. Of the pictures, 63%

KatRina [158]

The answer to your problem is 360

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2 years ago

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Find the value of the power. (2/3)3

Andreyy89

Answer:

The value is 27

Step-by-step explanation:

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2 years ago

What is the solution of this equation? 3a = 18

Triss [41]

3a =18

3a/3 = 18/3

a = 18/3

a = 6

Hope this helps

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2 years ago

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