Answer:
no, the confidence interval for the standard deviation σ cannot be expressed as 15.7
4.7There are three ways in which you can possibly express a confidence interval:
1)
inequalityThe two extremities of the interval will be each on one side of the "less then" symbol (the smallest on the left, the biggest on the right) and the symbol for the standard deviation (σ) will be in the middle:
11.0 < σ < 20.4
This is the first interval given in the question and it means <span>that the standard deviation can vary between 11.0 and 20.4
2)
interval</span>The two extremities will be inside a couple of round parenthesis, separated by a comma, always <span>the smallest on the left and the biggest on the right:
(11.0, 20.4)
This is the second interval given in the question.
3)
point estimate </span><span>
margin of error</span>
This is the most common way to write a confidence interval because it shows straightforwardly some important information.
However,
this way can be used only for the confidence interval of the mean or of the popuation, not for he confidence interval of the variance or of the standard deviation.
This is due to the fact that in order to calculate the confidence interval of the standard variation (and similarly of the variance), you need to apply the formula:

which involves a χ² distribution, which is not a symmetric function. For this reason, the confidence interval we obtain is not symmetric around the point estimate and the third option cannot be used to express it.
Answer:

Step-by-step explanation:


The problem state to multiply the function
and
so the symbol seems to be incorrect.
We actually want to calculate

Note

The system of inequalities that represents the given situation are x + y ≤ 20 and 15x + 10y ≥ 90.
The parameters needed to model the inequalities;
- amount made by Opal working for a photographer = $15 per hour
- amount made in the soccer team = $10 per hour
- minimum amount Opal needs to make a week = $90
- maximum number of hours Opal needs to work = 20 hours
Let the number of hours Opal works for a photographer = x
Let the number of hours Opal works in soccer team = y
The first system of inequality in the given situation is represented as;
x + y ≤ 20
The second system of inequality in the given situation is represented as;
15x + 10y ≥ 90
Thus, the system of inequalities that represents the given situation are x + y ≤ 20 and 15x + 10y ≥ 90.
learn more here: brainly.com/question/9774970
Answer:
about 50.8 cubic meters
Step-by-step explanation:
The formula for the volume of a cone is ...
V = (1/3)πr²h
Put the given values into the formula and do the arithmetic.
V = (1/3)π(3.4 m)²(4.2 m) = 16.194π m³
__
For π to calculator precision, this is ...
V ≈ 50.84 m³
For π = 3.14, this is ...
V ≈ 50.82 m³