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poizon [28]
3 years ago
9

The U.S. Bureau of Labor Statistics reports that of persons who usually work full-time, the average number of hours worked per w

eek is 43.4. Assume that the number of hours worked per week for those who usually work full-time is normally distributed. Suppose 12% of these workers work more than 48 hours. Based on this percentage, what is the standard deviation of number of hours worked per week for these workers?
Mathematics
1 answer:
alukav5142 [94]3 years ago
6 0

Answer:

The standard deviation of number of hours worked per week for these workers is 3.91.

Step-by-step explanation:

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the zscore of a measure X is given by

Z = \frac{X - \mu}{\sigma}

After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X. Subtracting 1 by the pvalue, we This p-value is the probability that the value of the measure is greater than X.

In this problem we have that:

The average number of hours worked per week is 43.4, so \mu = 43.4.

Suppose 12% of these workers work more than 48 hours. Based on this percentage, what is the standard deviation of number of hours worked per week for these workers.

This means that the Z score of X = 48 has a pvalue of 0.88. This is Z between 1.17 and 1.18. So we use Z = 1.175.

Z = \frac{X - \mu}{\sigma}

1.175 = \frac{48 - 43.4}{\sigma}

1.175\sigma = 4.6

\sigma = \frac{4.6}{1.175}

\sigma = 3.91

The standard deviation of number of hours worked per week for these workers is 3.91.

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weqwewe [10]

133 adult tickets were sold.

Step-by-step explanation:

Given,

Total tickets sold for school play = 399

Let,

x represent the number of children tickets sold.

y represent the number of adult tickets sold.

According to given statement;

x+y=399      Eqn 1

x = 2y           Eqn 2

Putting value of x from Eqn 2 in Eqn 1

2y+y=399\\3y=399

Dividing both sides by 3

\frac{3y}{3}=\frac{399}{3}\\y=133

133 adult tickets were sold.

Keywords: linear equation, substitution method

Learn more about substitution method at:

  • brainly.com/question/9231234
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3 years ago
PLEASE HELP- I NEED CORRECT ANSWER!!
Sergio [31]

Answer:

y > 4x + 2

Step-by-step explanation:

Y is above the line so the value has to be greater than the line (or equal to, possibly). So it represents > or ≥

A dotted/dashed line is non-inclusive, so it represents < or >.

Since it is both above the line AND non-inclusive, we would use this sign:

>

and this equation :)

y > 4x + 2

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Step-by-step explanation:

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the equation of a circle in general form is x squared + y squared + 20x + 12 y + 15 equals 0what is the equation of the circle i
Marrrta [24]

Answer: (x+10)^2+(y+6)^2=121

Step-by-step explanation:

The equation of a circle in the general form is:

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The equaton of  a circle in standard form is:

(x-h)^2+(y-k)^2=r^2

Where the center is at <em>(h, k)</em> and <em>r</em> is the radius

To write the equation of a circle from general form to standard form, you must complete the squaare, as you can see below:

1- Given the equation in general form:

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Then you obtain:

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