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2 years ago

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Sample of 3 items is selected at random from a box containing 20 items of which 4 aredefective. find the expected number of defe

ctive items in the sample.

1 answer:

azamat2 years ago

6 0

That's 54 I think. 20x3=60-4=54

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Of the 400 eighth-graders at pascal middle school, 117 take algebra, 109 take advanced computer, and 114 take industrial technol

Hatshy [7]

If 164 of the 400 eighth-graders take none of these courses, then 400-164=236 students take some courses.

Let x students take all three courses, then:

1. 70-x take only both algebra and advanced computer,

2. 34-x take only both algebra and industrial technology,

3. 29-x take only both advanced computer and industrial technology.

Now let's count how many student take only one course:

1. 117-(x+34-x+70-x)=13+x take algebra,

2. 109-(x+29-x+70-x)=10+x take advanced computer,

3. 114-(x+29-x+34-x)=51+x take industrial technology.

Now count all students that take some courses:

51+x+10+x+13+x+29-x+34-x+70-x+x=236,

x=236-51-10-13-29-34-70,

x=29.

Answer: all three courses take 29 students.

6 0

2 years ago

Read 2 more answers

Write a verbal expression for 6m-2

katrin2010 [14]

Answer: The difference of 6 times a number m and 2

Step-by-step explanation:

The way to write this expression is:

The difference of 6 times a number m and 2.

5 0

2 years ago

Counter example. The sum of three fractions with odd numerators is never 1/2

kolbaska11 [484]

1/6 + 1/6 + 1/6 = 3/6 = 1/2

8 0

2 years ago

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The national mean annual salary for a school administrator is $90,00 a year (The Cincinnati Enquirer, April 7, 2012). A school o

timofeeve [1]

Answer:31) The Coca-Cola Company reported that the mean per capita annual sales of its beverages in the United Sates was 423 eight-ounce servings. Suppose you are curious whether the consumption of Coca-Cola beverages is higher in Atlanta. A sample of 36 individuals from the Atlanta area showed a sample mean annual consumption of 460.4 eight ounce servings with a standard deviation of s=101.9 ounces. Using a=.05, do the sample results support the conclusion that mean annual consumption of Coca-Cola beverage products is higher in Atlanta

Step-by-step explanation:29) The national mean annual salary for a school administrator is $90,000 a year. (The Cincinnati Enquirer, April 7, 2012) A school official took a sample of 25 school administrators in the state of Ohio to learn about salaries in that state to see if they differed from the national average.

a) Formulate hypotheses that can be used to determine whether the population mean annaual administrator salary in Ohio differs from the nation mean of $90,000.

b) The sample data for 25 Ohio administrators is contained in the file named Administrator. What is the p-value for you hypothesis test in part (a)?

c) A a=.05 can your null hypothesis be rejected? What is your conclusion?

d) Repeat the preceding hypothesis test using the critical value approach.

6 0

2 years ago

Find the area of the part of the plane 5x + 4y + z = 20 that lies in the first octant.

BlackZzzverrR [31]

This part of the plane is a triangle. Call it $\mathcal S$ . We can find the intercepts by setting two variables to 0 simultaneously; we'd find, for instance, that $y=z=0$ means $5x=20\implies x=4$ , so that (4, 0, 0) is one vertex of the triangle. Similarly, we'd find that (0, 5, 0) and (0, 0, 20) are the other two vertices.

Next, we can parameterize the surface by

$\mathbf s(u,v)=\langle4(1-u)(1-v),5u(1-v),20v\rangle$

so that the surface element is

$\mathrm dS=\|\mathbf s_u\times\mathbf s_v\|=20\sqrt{42}(1-v)\,\mathrm du\,\mathrm dv$

Then the area of $\mathcal S$ is given by the surface integral

$\displaystyle\iint_{\mathcal S}\mathrm dS=20\sqrt{42}\int_{u=0}^{u=1}\int_{v=0}^{v=1}(1-v)\,\mathrm dv\,\mathrm du$
$\displaystyle=20\sqrt{42}\int_{v=0}^{v=1}(1-v)\,\mathrm dv=10\sqrt{42}\approx64.8074$

3 0

2 years ago