Answer:
20 or D.
Step-by-step explanation:
You simply plug in the values given for a and b:

So, your answer is 20.
Answer:
D.
Step-by-step explanation:
Ape x.
I hope this helps with you
Answer:
The 80% confidence interval for the mean number of words a third grader can read per minute is between 40.4 wpm and 40.8 wpm.
Step-by-step explanation:
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
.
So it is z with a pvalue of
, so 
Now, find M as such

In which
is the standard deviation of the population and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 40.6 - 0.2 = 40.4 words per minute.
The upper end of the interval is the sample mean added to M. So it is 40.6 + 0.2 = 40.8 words per minute.
The 80% confidence interval for the mean number of words a third grader can read per minute is between 40.4 wpm and 40.8 wpm.
Answer: X * 1 + Y * 3 + Z * 2 = 45
Step-by-step explanation: we will use bananas, apples and mangoes as the unknowns of the equation.
The value that you multiply to the unknowns will be multiplied by the price that corresponds to it.
These 3 products must be added to result in the total value that is 45.
X * 1 + Y * 3 + Z * 2 = 45