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:
P=3.5
P=2.667
Step-by-step explanation:
p=f/a
P=70/20
P=3.5
then f is increased by 10
f=70+10=80
and a is increased by 10
a=20+10
a=30
therefore; P=f/a
P=80/30
P=2.667
Answer:
There are 7,725 square feet of grass on the trapezoidal field
Step-by-step explanation:
Here in this question, we are interested in calculating the square feet of grass present on the trapezoidal field.
What this question is actually asking us is to calculate the area of the trapezoid-shaped grass field.
To calculate this area, what we need to do
simply is to use the formula for the area of a trapezoid.
Mathematically, the area of a trapezoid can be calculated using the formula;
Area of trapezoid = 1/2 * (a + b) * h
where a and b refers to the length of the parallel lengths of the trapezoid and h refers to the height of the trapezoid.
From the question;
a, b = 81ft and 125 ft
h = 75 ft
Substituting these values, we have :
Area = 1/2 * (81 + 125) * 75
Area = 1/2 * 206 * 75 = 83 * 75 = 7,725 ft^2
Answer:
x = ±6
Step-by-step explanation:
x^2/4=9
Multiply by 4 on each side
x^2/4 *4=9*4
x^2 = 36
Take the square root of each side
sqrt(x^2) = ±sqrt(36)
x = ±6
Use division or long division (ignore the decimal point)
Then put the decimal in the same spot as the dividend (the number being divided)