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3 years ago

(3x+4)-(-8-2x) simplified

Mathematics

1 answer:

goldenfox [79]3 years ago

7 0

Answer:

5x+12

Step-by-step explanation:

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Calculate the sample standard deviation and sample variance for the following frequency distribution of hourly wages for a sampl

lidiya [134]

Answer:

(a) The sample variance is 16.51

(a) The sample standard deviation is 4.06

Step-by-step explanation:

Given

$\begin{array}{cc}{Class} & {Frequency} & 8.26 - 10.00 & 20 &10.01-11.75 & 38 &11.76 - 13.50& 36 & 13.51-15.25 &25&15.26-17.00 &27 &\ \end{array}$

Solving (a); The sample variance.

First, calculate the class midpoints.

This is the mean of the intervals.

i.e.

$x_1 = \frac{8.26+10.00}{2} = \frac{18.26}{2} = 9.13$

$x_2 = \frac{10.01+11.75}{2} = \frac{21.76}{2} = 10.88$

$x_3 = \frac{11.76+13.50}{2} = \frac{25.26}{2} = 12.63$

$x_4 = \frac{13.51+15.25}{2} = \frac{28.76}{2} = 14.38$

$x_5 = \frac{15.26+17.00}{2} = \frac{32.26}{2} = 16.13$

So, the table becomes:

$\begin{array}{ccc}{Class} & {Frequency} & {x} & 8.26 - 10.00 & 20&9.13 &10.01-11.75 & 38 &10.88&11.76 - 13.50& 36 &12.63& 13.51-15.25 &25&14.38&15.26-17.00 &27 &16.13\ \end{array}$

Next, calculate the mean

$\bar x = \frac{\sum fx}{\sum f}$

$\bar x = \frac{20*9.13 + 38 * 10.88+36*12.63+25*14.38+27*16.13}{20+38+36+25+27}$

$\bar x = \frac{1845.73}{146}$

$\bar x = 12.64$

Next, the sample variance is:

$\sigma^2 = \frac{\sum f(x - \bar x)^2}{\sum f - 1}$

So, we have:

$\sigma^2 = \frac{20*(9.13-12.63)^2 + 38 * (10.88-12.63)^2 +...........+27 * (16.13 -12.63)^2}{20+38+36+25+27-1}$

$\sigma^2 = \frac{2393.6875}{145}$

$\sigma^2 = 16.51$

The sample standard deviation is:

$\sigma = \sqrt{\sigma^2}$

$\sigma = \sqrt{16.51}$

$\sigma = 4.06$

6 0

3 years ago

The total ticket sales for a soccer game were $1.260; 210 tickets were purchased. If all

Scorpion4ik [409]

It was 6 each because 1,260 divided by 210 is 6 and PLEASE MARK BRAINLIEST

6 0

3 years ago

Read 2 more answers

Hey lol i don't really need help on this cuz i could honestly look it up in the notes, but im lazy.

sertanlavr [38]

Theoretically =theory is potentially done, experimental is experiment XD XD. They both have to do with probability

3 0

2 years ago

A sphere has a radius of 5 ft.

leva [86]

Answer:

B. 100π

Step-by-step explanation:

The surface area of a sphere is given by

SA = 4 pi r^2

The radius is 5

SA = 4 * pi * r^2

SA = 4 * pi * 25

SA = 100 pi

8 0

2 years ago

Read 2 more answers

The Price family and the Jenkins family each used their sprinklers last summer. The water output rate for the Price family's spr

PIT_PIT [208]

Set up two equations:

1st: P (for Price family) + J (for Jenkins family) = 45 hours

2nd: 20P + 35J = 1200 liters

Rewrite the first equation as P = 45 – J

Replace P in the second equation:

20(45-J) + 35J = 1200

Simplify:

900 -20J + 35J = 1200

900 +15J = 1200

Subtract 900 from both sides:

15J = 300

Divide both sides by 15:

J = 300/15

J = 20

Jenkins used theirs for 20 hours

Price used theirs for 45-20 = 25 hours.

7 0

3 years ago