DO,K = (9, 6) (3, 2) The scale factor is
1 answer:
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Answer:
The 95% confidence interval for the mean amount of the increase is ($541.6, $588.4). This means that we are 95% sure that the mean amount of increase of all customers who charge at least $3,000 in a year is between these two values.
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 Z-table as such z has a p-value 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.
The lower end of the interval is the sample mean subtracted by M. So it is 565 - 23.4 = $541.6
The upper end of the interval is the sample mean added to M. So it is 565 + 23.4 = $588.4
The 95% confidence interval for the mean amount of the increase is ($541.6, $588.4). This means that we are 95% sure that the mean amount of increase of all customers who charge at least $3,000 in a year is between these two values.
Answer:
91%
Step-by-step explanation:
We can use the formula
- "is" is 90
- "of" is 99
- "percent" is what we are solving for so we will denote it as x
Substituting in our values we get
- We will need to cross multiply here to get (90)(100) = (x%)(99)
- This simplifies to 9000 = 99x%
- Dividing by 99 on both sides we get 90.9% → x = 91%