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4 years ago

7

Why do we prefer the t procedures to the z procedures for inference about a population mean? Group of answer choices z requires

that you know the population standard deviation σ which may be unrealistic. z can be used only for large samples. t does not require your data to be a random sample from the population. z requires that you know the population mean

1 answer:

denis-greek [22]4 years ago

5 0

Answer:

Correct option:

"z requires that you know the population standard deviation σ which may be unrealistic."

Step-by-step explanation:

The hypothesis test for significant population mean <em>μ</em> can be done either using the <em>z</em>-distribution of <em>t</em>-distribution.

Both the distribution require certain conditions to be fulfilled to use.

For using a <em>z</em>-distribution to perform a hypothesis test for <em>μ</em> the conditions to fulfilled are:

Population is Normally distributed.
The population standard deviation is known.
The sample selected is large.

For using a <em>t</em>-distribution to perform a hypothesis test for <em>μ</em> the conditions to fulfilled are:

Population is Normally distributed.
The sample selected is randomly selected.

If the population standard deviation is not known and we have to compute the sample standard deviation then use the <em>t</em>-distribution to perform the test for population mean.

Thus, the correct option is:

"z requires that you know the population standard deviation σ which may be unrealistic."

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The base and sides of a container is made of wood panels. The container does not have a lid. The base and sides are rectangular.

vfiekz [6]

Answer:

Minimum surface area = $70.77 cm^2$

Step-by-step explanation:

We are given that

Width of container=x cm

Length of container=2x cm

Volume of container= $54 cm^3$

We have to find the minimum surface areas that this container will have.

Volume of container= $l\times b\times h$

$x\times 2x\times h=54$

$2x^2h=54$

$h=\frac{54}{2x^2}=\frac{27}{x^2}$

Surface area of container= $2(b+l)h+lb$

Because the container does not have lid

Surface area of container= $S=2(2x+x)\times \frac{27}{x^2}+2x\times x$

$S=\frac{162}{x}+2x^2$

Differentiate w.r.t x

$\frac{dS}{dx}=-\frac{162}{x^2}+4x$

$\frac{dx^n}{dx}=nx^{n-1}$

Substitute $\frac{dS}{dx}=0$

$-\frac{162}{x^2}+4x=0$

$4x=\frac{162}{x^2}$

$x^3=\frac{162}{4}=40.5$

$x^3=40.5$

$x=(40.5)^{\frac{1}{3}}$

$x=3.4$

Again differentiate w.r.t x

$\frac{d^2S}{dx^2}=\frac{324}{x^3}+4$

Substitute x=3.4

$\frac{d^2S}{dx^2}=\frac{324}{(3.4)^3}+4=12.24>0$

Hence, function is minimum at x=3.4

Substitute x=3.4

Then, we get

Minimum surface area = $\frac{162}{(3.4)}+2(3.4)^2=70.77 cm^2$

8 0

3 years ago

Combining like terms although there has to be two terms<br> y-9+y-4

liberstina [14]

Answer:

2y - 13

Step-by-step explanation:

y - 9 + y - 4

2y - 9 - 4

2y - 13

3 0

3 years ago

Read 2 more answers

Frank got a gift for his sister and put it in a shoebox.

Leona [35]

Answer:

The correct answer is option C.

Step-by-step explanation:

Length of shoe box = l = 11 inches

Width of the shoes box = w = 6 inches

Height of the shoe box = h = 5 inches

Wrapping paper required t cover the shoe box will be equal to the total surface area of the shoe box.

Shoe box = Cuboid

Total surface area of the cuboid = 2(lw+wh+hl)

Total surface area of shoe box : T

$T=2\times (11 inch\times 6 inch+6 inch\times 5 inch+5 inch\times 11 inch)$

$=T = 302 inch^2$

Frank will need 302 square inches of wrapping paper to cover the shoe box.

5 0

3 years ago

Joe and Victoria take out a $200,000 loan for a real estate investment. The $200,000 is compounded monthly for 20 years at a 4.5

joja [24]

Ninety thousand dollars

5 0

3 years ago

Lannie ordered 12 copies of the same book for his book club members. The books cost $19 each, and the order has $15 shipping cha

docker41 [41]

Its is $243 because 12 x 19 + 15

5 0

3 years ago