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2 years ago

A sample of n = 4 scores has SS = 48. What is the estimated standard error for this sample? Group of answer choices

Mathematics

1 answer:

mylen [45]2 years ago

4 0

Answer:

Step-by-step explanation:

We have

n = 4 scores

SS = 48

For this question, we are required to find the estimated standard error

To get this, we first solve for the variance

S² = SS/n-1

= 48/4-1

= 48/3

= 16

Then S² = 16

S = √16

S = 4

Then the estimated standard error is given by:

S/√n

= 4/√4

= 4/2

= 2.

The estimated standard error is 2.

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Rhonda bought a new laptop for $800. The laptop depreciates, or loses, 20% of its value each year. The value of the laptop at a

zhuklara [117]

As per the problem,

Rhonda bought a new laptop for $800.

The laptop depreciates, or loses, 20% of its value each year.

The value of the laptop at a later time can be found using the formula

$A=P(1-r)^t.....(1)$

Here we have

P=$800

r=20%=0.20

t=2 years

Substitute the values in equation (1) we get

$A=800(1-0.2)^2\\ \\ \Rightarrow A=800(0.8)^2\\ \\ \Rightarrow A=800*0.64\\ \\ \Rightarrow A=512\\$

The laptop be worth in two years will be $512.

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2 years ago

find the centre and radius of the following Cycles 9 x square + 9 y square +27 x + 12 y + 19 equals 0

Citrus2011 [14]

Answer:

Radius: $r =\frac{\sqrt {21}}{6}$

$Center = (-\frac{3}{2}, -\frac{2}{3})$

Step-by-step explanation:

Given

$9x^2 + 9y^2 + 27x + 12y + 19 = 0$

Solving (a): The radius of the circle

First, we express the equation as:

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

Where

$r = radius$

$(h,k) =center$

So, we have:

$9x^2 + 9y^2 + 27x + 12y + 19 = 0$

Divide through by 9

$x^2 + y^2 + 3x + \frac{12}{9}y + \frac{19}{9} = 0$

Rewrite as:

$x^2 + 3x + y^2+ \frac{12}{9}y =- \frac{19}{9}$

Group the expression into 2

$[x^2 + 3x] + [y^2+ \frac{12}{9}y] =- \frac{19}{9}$

$[x^2 + 3x] + [y^2+ \frac{4}{3}y] =- \frac{19}{9}$

Next, we complete the square on each group.

For $[x^2 + 3x]$

1: Divide the $coefficient\ of\ x\ by\ 2$

2: Take the $square\ of\ the\ division$

3: Add this $square\ to\ both\ sides\ of\ the\ equation.$

So, we have:

$[x^2 + 3x] + [y^2+ \frac{4}{3}y] =- \frac{19}{9}$

$[x^2 + 3x + (\frac{3}{2})^2] + [y^2+ \frac{4}{3}y] =- \frac{19}{9}+ (\frac{3}{2})^2$

Factorize

$[x + \frac{3}{2}]^2+ [y^2+ \frac{4}{3}y] =- \frac{19}{9}+ (\frac{3}{2})^2$

Apply the same to y

$[x + \frac{3}{2}]^2+ [y^2+ \frac{4}{3}y +(\frac{4}{6})^2 ] =- \frac{19}{9}+ (\frac{3}{2})^2 +(\frac{4}{6})^2$

$[x + \frac{3}{2}]^2+ [y +\frac{4}{6}]^2 =- \frac{19}{9}+ (\frac{3}{2})^2 +(\frac{4}{6})^2$

$[x + \frac{3}{2}]^2+ [y +\frac{4}{6}]^2 =- \frac{19}{9}+ \frac{9}{4} +\frac{16}{36}$

Add the fractions

$[x + \frac{3}{2}]^2+ [y +\frac{4}{6}]^2 =\frac{-19 * 4 + 9 * 9 + 16 * 1}{36}$

$[x + \frac{3}{2}]^2+ [y +\frac{4}{6}]^2 =\frac{21}{36}$

$[x + \frac{3}{2}]^2+ [y +\frac{4}{6}]^2 =\frac{7}{12}$

$[x + \frac{3}{2}]^2+ [y +\frac{2}{3}]^2 =\frac{7}{12}$

Recall that:

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

By comparison:

$r^2 =\frac{7}{12}$

Take square roots of both sides

$r =\sqrt{\frac{7}{12}}$

Split

$r =\frac{\sqrt 7}{\sqrt 12}$

Rationalize

$r =\frac{\sqrt 7*\sqrt 12}{\sqrt 12*\sqrt 12}$

$r =\frac{\sqrt {84}}{12}$

$r =\frac{\sqrt {4*21}}{12}$

$r =\frac{2\sqrt {21}}{12}$

$r =\frac{\sqrt {21}}{6}$

Solving (b): The center

Recall that:

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

Where

$r = radius$

$(h,k) =center$

From:

$[x + \frac{3}{2}]^2+ [y +\frac{2}{3}]^2 =\frac{7}{12}$

$-h = \frac{3}{2}$ and $-k = \frac{2}{3}$

Solve for h and k

$h = -\frac{3}{2}$ and $k = -\frac{2}{3}$

Hence, the center is:

$Center = (-\frac{3}{2}, -\frac{2}{3})$

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2 years ago

Find P(x)=... polynomial

Aneli [31]

Answer: D) P(x) = -23

Step-by-step explanation:

Substitute 2 for x:

1 - 2(2)^2-3(2)^2+4(2)

Exponent

1-2(4)-3(8)+4(2)

Multiply

1-8-24+8

Combine like terms

-23

<em>Hope it helps <3</em>

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2 years ago

The 40th parallel of north latitude runs across the United States through Philadelphia, Indianapolis, and Denver. At this latitu

Ronch [10]

Answer:

793.25 mi/hr

Step-by-step explanation:

Given that:

The radius of the earth is = 3030 miles

The angular velocity = $\dfrac{\pi}{12} rads$

If a jet flies due west with the same angular velocity relative to the ground at the equinox;

We are to determine the How fast in miles per hour would the jet have to travel west at the 40th parallel for this to happen.

NOW;

Distance s is expressed by the relation

s = rθ

$s = 3030(\frac{\pi}{12} )$

s = 793.25

The speed which depicts how fast in miles per hour the jet would have traveled is :

$speed (v) = \frac{s}{t}$

$v = \frac{793.25}{1}$

v = 793.25 mi/hr

Hence, the jet would have traveled 793.25 mi/hr due west at the 40th parallel for this to happen.

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3 years ago

Aaron borrows $150 from his friend Austin. He has to pay the money back in 4 monthly installments. Each month he wants to pay ha

Y_Kistochka [10]

Austin should pay $75 the first month, and 37.50 for the remaining of the 2 months

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