Luis and Darcy are required to write essays for their English class. The table shows the number of words they wrote for 10 rando
2 answers:
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Answer:
We would have to take a sample of 62 to achieve this result.
Step-by-step explanation:
Confidence level of 95%.
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of .
That is z with a pvalue of , so Z = 1.96.
Now, find the margin of error M as such
In which is the standard deviation of the population and n is the size of the sample.
Assume that the standard deviation in the amount of caffeine in 8 ounces of decaf coffee is known to be 2 mg.
This means that
If we wanted to estimate the true mean amount of caffeine in 8 ounce cups of decaf coffee to within /- 0.5 mg, how large a sample would we have to take to achieve this result?
We would need a sample of n.
n is found when . So
Dividing both sides by 0.5
Rounding up
We would have to take a sample of 62 to achieve this result.
Answer:
22
Step-by-step explanation:
Find f(-3) :
f(x) = x² + 2x for x ≤ -3
That means for those values of x, less than or equal to -3, this is the function.
So, f(-3) = (-3)² + 2(-3) = 9 - 6 = 3
Now, f(-1) :
From the given data, we see it is: f(x) = 2
We take this because -1 lies between -3 and 4.
Now, f(-1) = 2
=>
For f(4) :
Clearly, the function is:
Therefore, <u>f(-3) + f(-1) - f(4) = 3 + 18 - (-1) = 3 + 18 + 1 = 22.</u>