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1 year ago

Omar recorded the number of hours he worked each week for a year. Below is a random sample that he took from his data.

Mathematics

1 answer:

lidiya [134]1 year ago

7 0

Answer: B) 4

Step-by-step explanation:

Using the formula

Standard deviation = √( (Σ ( x - π)²)/n)

To get the standard deviation, first we workout the Mean which is the simple average of the data set

n = 4

(13 + 17 + 9 + 21) / 4 = 60/4 = 15

Mean(x) = 15

Then (x-π)²

13 - 15 = (-2)² = 4

17 - 15 = (2)² = 4

9 - 15 = (-6)² = 36

21 - 15 = (6)² = 36

Σ ( x - π)² = (4 + 4 + 36 + 36) = 80

Standard deviation = √( (Σ ( x - π)²)/n

= √ (80/4)

=√20

= 4.47

= 4

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A car tire with a radius of 16inches is turning at a rate of 120 revolutions per minute. Find the exact linear speed of the tire

anygoal [31]

Answer:

The speed of the tyre of the car is 1002.24 feet per minute .

Step-by-step explanation:

Given as :

The radius of the car wheel = r = 16 inches

Since 12 inches = 1 feet

So, 16 inches = $\frac{1}{12}$ ×16 = 1.33 feet

The number of revolution of the wheel = 120 revolution per minute

Let The speed of the wheel = s feet per minute

The circumference of wheel = 2 × $\pi$ × radius

where $\pi$ = 3.14

or, circumference = 2 × 3.14 × 1.33

Or, Circumference = 8.352 feet

Now , Speed = circumference of wheel × number of revolution

or, Speed = 8.352 feet × 120 revolution per minute

∴ Speed = 1002.24 feet per minute

Hence The speed of the tyre of the car is 1002.24 feet per minute . Answer

4 0

2 years ago

nikki backyard is in the shape of a rectangle. the length is 27 feet. The width is one-third the length plus 4 feet. write and e

PIT_PIT [208]

Answer:

A= Length x Width

A= 27 x (1/3 x 27 + 4)

A=27 x (9 + 4)

A= 27 x 13

A= 351

Step-by-step explanation:

4 0

1 year ago

Two processes are used to produce forgings used in an aircraft wing assembly. Of 200 forgings selected from process 1, 10 do not

tangare [24]

Answer:

$\bar p_1=0.05\\\bar p_2=0.067$

b-Check illustration below

c.(-0.0517,0.0177

Step-by-step explanation:

a.let $p_1 \& p_2$ denote processes 1 & 2.

For $p_1$ : T1=10,n1=200

For $p_2$ :T2=20,n2=300

Therefore

$\bar p_1=\frac{t_1}{N_1}=\frac{10}{200}=0.05\\\bar p_2=\frac{t_2}{N_2}=\frac{20}{300}=0.067$

b. To test for hypothesis:-

$H_0:p_1=p_2\\H_A=p_1\neq p_2\\\alpha=0.05$

ii.For a two sample Proportion test

$Z=\frac{\bar p_1-\bar p_2}{\sqrt(\bar p(1-\bar p)(\frac{1}{n_1}+\frac{1}{n_2})}\\$

iii. for $\frac{\alpha}{2}=(-1.96,+1.96)$ (0.5 alpha IS 0.025),

reject $H_o$ if $|Z|>1.96$

iv. Do not reject $H_o$ . The noncomforting proportions are not significantly different as calculated below:

$z=\frac{0.050-0.067}{\sqrt {(0.06\times0.94)\times \frac{1}{500}}}$

z=-0.78

c. $(1-\alpha).100\%$ for the p1-p2 is given as:

$(\bar p_1-\bar p_2)\pm Z_0_._5_\alpha \times \sqrt \frac{ \bar p_1(1-\bar p_1)}{n_1}+\frac{\bar p_2(1-\bar p_2)}{n_2}\\\\=(0.05-0.067)\pm 1.645 \times \sqrt \ \frac{0.05+0.95}{200}+\frac{0.067+0.933}{300}\\$

=(-0.0517,+0.0177)

*CI contains o, which implies that proportions are NOT significantly different.

4 0

2 years ago

8x + 6y = 10

juin [17]

It could be D or C
The system has two solutions
x = .8 y = .6

OR if you think about it , (x=.8 y=.6) could be considered THE solution.
I would go with choice C

6 0

2 years ago

Read 2 more answers

The Foot Locker is having a 60% off sale on shorts. John paid $18 for a pair of shorts. What was the original price of the short

AURORKA [14]

Answer:

$30 is the price of the original pair of sneakers.

Step-by-step explanation:

You wanna cross multiply so you put :

18. 60

_ = _

x. 100

You multiply 18 the cost of the sneakers by 100 and then divide the product (1800) by 60 and you get $30.

MARK ME AS BRAINLIEST!

6 0

1 year ago