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3 years ago

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In order to estimate the mean amount of time computer users spend on the internet each month, how many computer users must be s

urveyed in order to be 9595% confident that your sample mean is within 1010 minutes of the population mean? Assume that the standard deviation of the population of monthly time spent on the internet is 221221 min. What is a major obstacle to getting a good estimate of the population mean? Use technology to find the estimated minimum required sample size.

1 answer:

levacccp [35]3 years ago

7 0

Answer:

1877 computer users

Step-by-step explanation:

We have that for 95% of confident, the value of z has a value of 1.96 (attached table about it), they also mention the margin of error (E) that is 10 and finally the standard deviation (sd) that has a value of 221.

We apply the following formula:

n = [z * sd / E] ^ 2

replacing:

n = [1.96 * 221/10] ^ 2

n = 1876.27

that is, the minimum sample size is 1877

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A cone-shaped pile of sawdust has a base diameter of 38 feet, and is 14 feet tall. Find the volume of the pile

Romashka-Z-Leto [24]

Answer:

Given: Diameter of cone = 38 feet and height of cone = 14 feet.

Volume of cone V with radius r is one-third the area of the base B times the height h.

i,e $V = \frac{1}{3} B \cdot h$ = $\frac{1}{3} \pi r^2h$ ......[1]

,where B = $\pi r^2$

First find the radius(r);

Using Diameter(D) = 2r

38 =2r

Divide both side by 2 we get;

$\frac{38}{2} =\frac{2r}{2}$

Simplify:

19 = r

or r =19 feet

Now, substitute the value of r = 19 feet and h = 14 feet in [1] [ Use value of $\pi = \frac{22}{7}$ ]

then, we have:

$V = \frac{1}{3} \pi r^2h = \frac{1}{3} \cdot \frac{22}{7} \cdot (19)^2 \cdot (14)$

or

V = $=\frac{1}{3}\cdot 22 \cdot 19 \cdot 19 \cdot 2 = \frac{22 \cdot 19 \cdot 19 \cdot 2}{3}$

or

V = $\frac{15884}{3} =5,294.66667$ ≈ 5,294.67 cubic feet.

therefore, the volume of pile is; ≈ 5,294.67 cubic feet.

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3 years ago

1. Find the capacity in litres of a bucket 24cm in

Sav [38]

Answer:

6.36l

Step-by-step explanation:

We compute first the volume:

V=pi×h/3×(R²+r²+rR), where h=20cm is the height, R=24/2=12cm is the top radius, r=16/2=8cm is the bottom radius.

We get: V=pi×20/3(12²+8²+12×8)=

20×pi/3(144+64+96)cm³

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By definition, 1dm³=1l, so the capacity is 6.36l

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4 years ago

For the function below, find a formula for the upper sum obtained by dividing the interval [a comma b ][a,b] into n equal subin

Vlad [161]

Answer:

See below

Step-by-step explanation:

We start by dividing the interval [0,4] into n sub-intervals of length 4/n

$[0,\displaystyle\frac{4}{n}],[\displaystyle\frac{4}{n},\displaystyle\frac{2*4}{n}],[\displaystyle\frac{2*4}{n},\displaystyle\frac{3*4}{n}],...,[\displaystyle\frac{(n-1)*4}{n},4]$

Since f is increasing in the interval [0,4], the upper sum is obtained by evaluating f at the right end of each sub-interval multiplied by 4/n.

Geometrically, these are the areas of the rectangles whose height is f evaluated at the right end of the interval and base 4/n (see picture)

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but

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so the upper sum equals

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4 years ago

Which statement describes the function y=ax^n when a=1 and n is odd?

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ANSWER

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EXPLANATION.

The given function is

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When a=1,

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Since n is odd,

$f(-x)=-{( x)}^{n}$

$\Rightarrow f(-x)=-f(x)$

This implies that, the function

$y={x}^{n}$

is symmetric with respect to origin.

The correct answer is B

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3 years ago

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Allushta [10]

The formula for arc length is...

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