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3 years ago

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Recently, a random sample of 13-18 year olds was asked, "How much do you currently have in savings?" The data in the table re

present the responses to the survey. Approximate the mean and standard deviation amount of savings.

1 answer:

Sonbull [250]3 years ago

6 0

Answer:

μ = 235.38

σ = 234.54

Step-by-step explanation:

Assuming the table is as follows:

$\left[\begin{array}{cc}Savings&Frequency\\\$0-\$199&339\\\$200-\$399&86\\\$400-\$599&55\\\$600-\$799&18\\\$800-\$999&11\\\$1000-\$1199&8\\\$1200-\$1399&3\end{array}\right]$

This is an example of grouped data, where a range of values is given rather than a single data point. First, find the total frequency.

n = 339 + 86 + 55 + 18 + 11 + 8 + 3

n = 520

The mean is the expected value using the midpoints of each range.

μ = (339×100 + 86×300 + 55×500 + 18×700 + 11×900 + 8×1100 + 3×1300) / 520

μ = 122400 / 520

μ = 235.38

The variance is:

σ² = [(339×100² + 86×300² + 55×500² + 18×700² + 11×900² + 8×1100² + 3×1300²) − (520×235.38²)] / (520 − 1)

σ² = 55009.7

The standard deviation is:

σ = 234.54

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2 3/7 + (-1 3/4) i need help please

julsineya [31]

Answer:

1/28

Step-by-step explanation:

7 0

3 years ago

A sailor is 30m above the water in the crow's nest on a sailboat. The sailor encounters an orca surface at an angle of depressio

Natali [406]

Given :

A sailor is 30 m above the water in the crow's nest on a sailboat.

The sailor encounters an orca surface at an angle of depression of 15 degrees.

The crows nest is 20 m horizontally from the bow (front) of the boat.

To Find :

How far in front of the boat is the orca.

Solution :

Let, distance of boat front from the crow's nest is x.

So,

$\dfrac{30}{20+x}=tan \ 15^{\circ}\\\\x=\dfrac{30}{tan \ 15^{\circ}}-20\\\\x=111.94-20\\\\x=91.94\ m$

Hence, this is the required solution.

4 0

3 years ago

X2 =5. What is the answer for X

grin007 [14]

Answer:

x=2.5

Step-by-step explanation:

First, you do 5 divided by 2, because you are trying to find a missing factor. After that, your answer, which is 2.5, is what x equals.

Hope that helps!

7 0

3 years ago

Read 2 more answers

On a coordinate plane, kite W X Y Z is shown. Point W is at (negative 3, 3), point X is at (2, 3), point Y is at (4, negative 4)

xz_007 [3.2K]

Answer:

$P = 10 + 2\sqrt{53}$ units

Step-by-step explanation:

Given

Shape: Kite WXYZ

W (-3, 3), X (2, 3),

Y (4, -4), Z (-3, -2)

Required

Determine perimeter of the kite

First, we need to determine lengths of sides WX, XY, YZ and ZW using distance formula;

$d = \sqrt{(x_1 - x_2)^2 + (y_1 - y_2)^2}$

For WX:

$(x_1, y_1)\ (x_2,y_2) = (-3, 3),\ (2, 3)$

$WX = \sqrt{(-3 - 2)^2 + (3 - 3)^2}$

$WX = \sqrt{(-5)^2 + (0)^2}$

$WX = \sqrt{25}$

$WX = 5$

For XY:

$(x_1, y_1)\ (x_2,y_2) = (2, 3)\ (4,-4)$

$XY = \sqrt{(2 - 4)^2 + (3 - (-4))^2}$

$XY = \sqrt{-2^2 + (3 +4)^2}$

$XY = \sqrt{-2^2 + 7^2}$

$XY = \sqrt{4 + 49}$

$XY = \sqrt{53}$

For YZ:

$(x_1, y_1)\ (x_2,y_2) = (4,-4)\ (-3, -2)$

$YZ = \sqrt{(4 - (-3))^2 + (-4 - (-2))^2}$

$YZ = \sqrt{(4 +3)^2 + (-4 +2)^2}$

$YZ = \sqrt{7^2 + (-2)^2}$

$YZ = \sqrt{49 + 4}$

$YZ = \sqrt{53}$

For ZW:

$(x_1, y_1)\ (x_2,y_2) = (-3, -2)\ (-3, 3)$

$ZW = \sqrt{(-3 - (-3))^2 + (-2 - 3)^2}$

$ZW = \sqrt{(-3 +3)^2 + (-2 - 3)^2}$

$ZW = \sqrt{0^2 + (-5)^2}$

$ZW = \sqrt{0 + 25}$

$ZW = \sqrt{25}$

$ZW = 5$

The Perimeter (P) is as follows:

$P = WX + XY + YZ + ZW$

$P = 5 + \sqrt{53} + \sqrt{53} + 5$

$P = 5 + 5 + \sqrt{53} + \sqrt{53}$

$P = 10 + 2\sqrt{53}$ units

6 0

4 years ago

PLEASE HELP ASAP! BRAINLIEST TO BEST/RIGHT ANSWER

Semenov [28]

= 9 * 10^5 * 3 * 10^10

= 27 * 10^5 * 10^10

= 27 * 10^15

= 2.7 * 10^16 - The best selection appears to be the first option.

Good luck :)

4 0

3 years ago