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3 years ago

Please help me answer

Mathematics

1 answer:

frosja888 [35]3 years ago

4 0

Answer:

i think its 48

Step-by-step explanation:

do 39+9 because the 9 is negative

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The random variable x represents the number of computers that families have along with the corresponding probabilities. Find the

Elena L [17]

Answer:

The correct option is (d).

Step-by-step explanation:

The complete question is:

The random variable x represents the number of computers that families have along with the corresponding probabilities. Use the probability distribution table below to find the mean and standard deviation for the random variable x.

x : 0 1 2 3 4

p (x) : 0.49 0.05 0.32 0.07 0.07

(a) The mean is 1.39 The standard deviation is 0.80

(b) The mean is 1.39 The standard deviation is 0.64

(c)The mean is 1.18 The standard deviation is 0.64

(d) The mean is 1.18 The standard deviation is 1.30

Solution:

The formula to compute the mean is:

$\text{Mean}=\sum x\cdot p(x)$

Compute the mean as follows:

$\text{Mean}=\sum x\cdot p(x)$

$=(0\times 0.49)+(1\times 0.05)+(2\times 0.32)+(3\times 0.07)+(4\times 0.07)\\\\=0+0.05+0.64+0.21+0.28\\\\=1.18$

The mean of the random variable x is 1.18.

The formula to compute variance is:

$\text{Variance}=E(X^{2})-[E(X)]^{2}$

Compute the value of E (X²) as follows:

$E(X^{2})=\sum x^{2}\cdot p(x)$

$=(0^{2}\times 0.49)+(1^{2}\times 0.05)+(2^{2}\times 0.32)+(3^{2}\times 0.07)+(4^{2}\times 0.07)\\\\=0+0.05+1.28+0.63+1.12\\\\=3.08$

Compute the variance as follows:

$\text{Variance}=E(X^{2})-[E(X)]^{2}$

$=3.08-(1.18)^{2}\\\\=1.6876$

Then the standard deviation is:

$\text{Standard deviation}=\sqrt{\text{Variance}}$

$=\sqrt{1.6876}\\\\=1.2990766\\\\\approx 1.30$

Thus, the mean and standard deviation for the random variable x are 1.18 and 1.30 respectively.

The correct option is (d).

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3 years ago

What is the solution to the system -2x + y = 6 and y= 2x - 3?

Irina18 [472]

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-2x + 2x - 3 = 6

- 3 = 6 .....no solutions....

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