A recent drug survey showed an increase in use of drugs and alcohol among local high school students as compared to the national
1 answer:
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Answer:
The 95% CI for the difference of means is:
Step-by-step explanation:
<em>The question is incomplete:</em>
<em>"Find a 95% confidence interval on the difference of the towels mean absorbency produced by the two processes. Assumed that the standard deviations are estimated from the data. Round to two decimals places."</em>
Process 1:
- Sample size: 10
- Mean: 200
- S.D.: 15
Process 2:
- Sample size: 4
- Mean: 300
- S.D.: 50
The difference of the sample means is:
The standard deviation can be estimated as:
The degrees of freedom are:
The t-value for a 95% confidence interval and 12 degrees of freedom is t=±2.179.
Then, the confidence interval can be written as:
Answer:
x=2, y=4
Step-by-step explanation:
When using elimination, the objective is to elimate one variable. In this case, we see that "y" can easily be eliminated by adding the two equations together since you will get 3y + (-3y) which will eliminate y because the value would become 0, letting us solve for x.
Then we get
, because the y's will eliminated, and 8x+7x is 15x, and 28+2 is 30.
Then divide by 15 on both sides and you get x=2
If x=2, then we can substitute that value into any of the previous given equations and find the value of y.
8×2 +3y = 28
16+3y=28
3y=12
y=4
So the answer to your system of equations would be x=2, and y=4
You can substitute the answers we found to see that they satisfy the equation.
Hope this helped.