The phrasing "nine times out of ten" means 9/10 = 0.90 = 90% is the confidence level. We're confident 90% of the time that the confidence interval captures the population parameter we're after (in this case mu = population mean)
The portion "have an average score within 5% of 75%" means that 75% = 0.75 is the center of the confidence interval, and it goes as low as 0.75 - 0.05 = 0.70 and as high as 0.75 + 0.05 = 0.80
This confidence interval is from 70% to 80%, meaning that nine times out of ten, we're confident that the average score is between 70% and 80%
We write the confidence interval as (0.70, 0.80). It's common to use the notation (L, U) to indicate the lower (L) and upper (U) boundaries. You might see the notation in the form L < mu < U. If so, then it would be 0.70 < mu < 0.80; either way they mean the same thing.
The margin of error is 0.05 as its the 5% radius of the interval. It tells us how far the most distant score is from the center (75%)
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In summary, we have these answers
- confidence level = 90%
- margin of error = 5% = 0.05
- confidence interval = (0.70, 0.80)
- interpretation = We're 90% confident that the average exam score is between 0.70 and 0.80
Answer:
15
Step-by-step explanation:
There are 4/4 to make a whole so 2 1/2 cups would be 10 'scoops' and 1 1/4 would be 5 'scoops'. Add 10 + 5 to get a total of 15 scoops.
Hope that helps and have a great day!
Answer:
3/2x
Step-by-step explanation:
-2y = -3x+18
y = 3/2x-9
The altitude is 177 feet below sea level after being lowered.
The balloon rises 120 feet after 12 seconds and then is dropped 15 feet. So 120 - 15 = 105. And 282 - 105 = 177
