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3 years ago

Can someone help with 31?!!!

Mathematics

1 answer:

Anton [14]3 years ago

8 0

Standard deviation is the data's average variation from the mean, so if you have a standard deviation of 0, that means all of the student's grades are the same grade.

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In Applied Life Data Analysis (Wiley, 1982), Wayne Nelson presents the breakdown time of an insulating fluid between electrodes

ale4655 [162]

Answer:

The sample mean is $\bar{x}=14.371$ min.

The sample standard deviation is $\sigma = 18.889$ min.

Step-by-step explanation:

We have the following data set:

$\begin{array}{cccccccc}0.15&0.82&0.81&1.44&2.70&3.28&4.00&4.70\\4.96&6.49&7.25&8.03&8.40&12.15&31.89&32.47\\33.79&36.80&72.92&&&&&\end{array}$

The mean of a data set is commonly known as the average. You find the mean by taking the sum of all the data values and dividing that sum by the total number of data values.

The formula for the mean of a sample is

$\bar{x} = \frac{{\sum}x}{n}$

where, $n$ is the number of values in the data set.

$\bar{x}=\frac{0.15+0.82+0.81+1.44+2.7+3.28+4+4.7+4.96+6.49+7.25+8.03+8.4+12.15+31.89+32.47+33.79+36.80+72.92}{19}\\\\\bar{x}=14.371$

The standard deviation measures how close the set of data is to the mean value of the data set. If data set have high standard deviation than the values are spread out very much. If data set have small standard deviation the data points are very close to the mean.

To find standard deviation we use the following formula

$\sigma = \sqrt{ \frac{ \sum{\left(x_i - \overline{x}\right)^2 }}{n-1} }$

The mean of a sample is $\bar{x}=14.371$ .

Create the below table.

Find the sum of numbers in the last column to get.

$\sum{\left(x_i - \overline{X}\right)^2} = 6422.0982$

$\sigma = \sqrt{ \frac{ \sum{\left(x_i - \overline{x}\right)^2 }}{n-1} } = \sqrt{ \frac{ 6422.0982 }{ 19 - 1} } \approx 18.889$

7 0

2 years ago

Alexis’s cell phone company charges her $45 a month for phone service plus $0.50 for each text message. How many text messages d

ValentinkaMS [17]

Answer:

Step-by-step explanation:

62 - 45 = 17

17 x 2 = 34

8 0

2 years ago

The length, l, that a spring is stretched varies directly as the amount of force, F, applied to the end of the spring. When a fo

Elina [12.6K]

Answer:

C. 4.5 inches

Step-by-step explanation:

Given the following data;

Force, F = 10 pounds

Extension, e = 3 inches

First of all, we would determine the spring constant (k) using the following formula;

Force = spring constant * extension

10 = spring constant * 3

Spring constant = 10/3

Spring constant = 3.33 pounds per inches.

Next, we would find the extension of the spring when a force of 15 pounds is applied;

F = ke

15 = 3.33 * e

Extension, e = 15/3.33

Extension, e = 4.5 inches.

7 0

2 years ago

Cheryl has 56$ and wants to buy as many notebooks as she can to donate to her school. If each notebook cost $1.60, which inequal

Len [333]

1.60n<56
it should be greater than or equal to because if n is the amount of notebooks she can buy than n times 1.60 needs to be less or equal to $56

3 0

2 years ago

Please someone help me

Anna007 [38]

Your answer would have to be B. 112 cm.

5 0

2 years ago