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3 years ago

13

-x-7y=9 -x+9y=-23 How do I answer it

1 answer:

ipn [44]3 years ago

6 0

Change one "x" to a positive by multiplying everything to a -1. Then add the equations to make one, solve for "y". After you get "y" plug it in to get "x". Hope that helps.

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How do i find joint relative frequency?

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A study sampled 350 upperclassmen (Group 1) and 250 underclassmen (Group 2) at high schools around the city of Portland. The stu

iVinArrow [24]

Answer:

$-0.061 < P_1 -P_2< 0.025$

Step-by-step explanation:

Give data:

$n_1 = 350$

$n_2 =250$

$x_1 = 23$

$x_2 = 21$

$\hat{P} 1 = \frac{x_1}{n_1} = \frac{23}{350} = 0.066$

$\hat{P} 2 = \frac{x_2}{n_2} = \frac{21}{250} = 0.084$

for 95% confidence interval

$\alpha = 1 - 0.95 = 0.05 and \alpha/2 = 0.025$

$z_{\alpha/2} = 1.96$ from standard z- table

confidence interval for P_1 and P_2 is

$\hat{P} 1 - \hat{P} 2 \pm z_{\alpja/2} \sqrt{\frac{\hat{P} 1(1-\hat{P} 1)}{n_1} +\frac{\hat{P} 2(1-\hat{P} 2)}{n_2}}$

$(0.066 - 0.084) \pm 1.96 \sqrt{\frac{0.066(1-0.066)}{350} +\frac{0.084(1-0.084)}{250}}$

$-0.018 \pm 0.043$

confidence interval is

$-0.018 - 0.043 < P_1 -P_2$

$-0.061 < P_1 -P_2< 0.025$

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3 years ago

Write the numbers in the blanks that make this equation true.<br><br> ( 2 + 1 ) + 3 = 2 + ( _ + _ )

Marta_Voda [28]

(2+1)+3=2+(2+2)

Any two numbers that add to 4.

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