X+3y=7
x-3y=1
add them together

x+3y=7
<u>x-3y=1 +
</u>2x+0y=8

2x=8
divide 2
x=4
subsitute
x+3y=7
4+3y=7
subtract 4
3y=3
divid 3
y=1

x=4
y=1

answer is A
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6 0

3 years ago

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Assume a researcher recruits 150 African American and Caucasian individuals taking warfarin to determine if there is a differenc

Anettt [7]

Answer:

Z=11.0

Step-by-step explanation:

Let Caucasian individuals be the population 1 and African American be the population 2. So, we are given that

n=150

n1=75

mean1=xbar1=6.1.

standard deviation1=S.D1=σ1=1.1.

Variance1=V(x1)=σ1²=1.1²=1.21.

n2=75.

mean2=xbar2=4.3.

standard deviation2=S.D2=σ2=0.9.

Variance2=V(x2)=σ2²=0.9²=0.81.

The z-statistic is

$Z=\frac{xbar1-xbar2}{\sqrt{\frac{V(x1)}{n1}+ \frac{V(x2)}{n2} } }$

$Z=\frac{6.1-4.3}{\sqrt{\frac{1.21}{75}+ \frac{0.81}{75} } }$

$Z=\frac{1.8}{\sqrt{0.0161+ 0.0108 } }$

$Z=\frac{1.8}{\sqrt{0.0269 } }$

$Z=\frac{1.8}{0.164 } }$

Z=10.97

Z=11.0

So, the z value obtained while calculating the test statistic is approximately 11.0.

4 0

3 years ago

Why is it important to know how to use area or volume in real life?

Jet001 [13]

It’s important because you may doing something that includes that and you don’t have a ruler etc..

4 0

3 years ago

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