Using the t-distribution to build the 99% confidence interval, it is found that:
- The margin of error is of 3.64.
- The 99% confidence interval for the population mean is (19.36, 26.64).
<h3>What is a t-distribution confidence interval?</h3>
The confidence interval is:

In which:
is the sample mean.
- s is the standard deviation for the sample.
The critical value, using a t-distribution calculator, for a two-tailed 95% confidence interval, with 21 - 1 = 20 df, is t = 2.086.
The other parameters are given as follows:

The margin of error is given by:

Hence the bounds of the interval are:


The 99% confidence interval for the population mean is (19.36, 26.64).
More can be learned about the t-distribution at brainly.com/question/16162795
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Answer:
<em>-(6 1/3-1/6x 36=216</em>
Hope I helped
Question 9 answer is 0.375
Question 10 answer is 0.03125
Answer:
It'll take him 1/4 hours to decorate the two signs.
Step-by-step explanation:
In order to know how long Roberto will take to decorate all the signs we need to find their surface area, since they're rectangular their area is given by the product of their dimensions.
First sign:
area1 = (2/3)*(1/4) = 2/12 = 1/6 foot²
Second sign:
area2 = (1/2)*(1/3) = 1/6 foot²
The total area he has to paint is the sum of their individual areas, so we have:
total area = area1 + area2 = 1/6 + 1/6 = 2/6 = 1/3 foot²
To find out how long he'll take to decorate this area we can use a rule of three as shown bellow:
3/4 hour -> 1 foot²
x hour -> 1/3 foot²
x = (3/4)*(1/3) = 1/4 hours