Answer:
ok and thank you for point
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.
Previous crime rate = c incidents per 1,000 people
Reduction in crime rate after batman brought the joker to justice = 12%
Hence, new crime rate (per 1,000 people) would be = c - 12%×c
⇒ New crime rate (per 1,000 people) would be = c - 0.12×c
⇒ New crime rate (per 1,000 people) would be = 0.88×c
Hence, now the crime rate is 0.88×c per 1,000 people.
Answer:
c
Step-by-step explanation:

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