PLEASE HELP ME!!! Its easy!
2 answers:
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Answer:
(-13, -4)
Step-by-step explanation:
It is about as easy to try the solutions as it is to find them from scratch.
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However, we can determine which one it is by adding twice the second equation to the first.
(-2a +3b) +2(a -4b) = (14) +2(3)
-5b = 20
b = -4 . . . . . . matches the first choice
Answer:
The 95% confidence interval for the population mean rating is (5.73, 6.95).
Step-by-step explanation:
We start by calculating the mean and standard deviation of the sample:
We have to calculate a 95% confidence interval for the mean.
The population standard deviation is not known, so we have to estimate it from the sample standard deviation and use a t-students distribution to calculate the critical value.
The sample mean is M=6.34.
The sample size is N=50.
When σ is not known, s divided by the square root of N is used as an estimate of σM:
The degrees of freedom for this sample size are:
The t-value for a 95% confidence interval and 49 degrees of freedom is t=2.01.
The margin of error (MOE) can be calculated as:
Then, the lower and upper bounds of the confidence interval are:
The 95% confidence interval for the mean is (5.73, 6.95).