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2 years 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]2 years 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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The quotient of 9.2 x 10 6 and 2.3 x 10 2 expressed in scientific notation is

Virty [35]

What we know:
quotient 9.2 x 10^6/ 2.3 x 10²
in quotients exponents are subtracted of they have the same base, for example 10^6 and 10² have the same base of 10

What we need to find: quotient 9.2 x 10^6/ 2.3 x 10²
9.2 x 10^6
-------------- = 4 x 10^4
2.3 x 10²

Here in this problem I divided 9.2 by 2.3 and got 4, since the solution was simple and clean meaning no repeated decimals I went ahead and divided the 10^6 by 10^2 and got 10^4.

Another method would be to expand both numbers then divide and do scientific notation again.
Remember to change to normal notation you move the decimal to the right using the number of the exponent.

9.2 x 10^6= 9200000
2.3 x 10²= 230

920000/230=40000

40000= 4 x 10^4 scientific notation

Use the method that is best for you or just know you can use either method to check your work.

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2 years ago

A sequence is defined recursively using the formula f(n + 1) = –0.5 f(n) . If the first term of the sequence is 120, what is f(5

balu736 [363]

Hello,

$f(1)=120\\
 f(2)=-\frac{1}{2}*120=-60\\ 
 f(3)=-\frac{1}{2} *(-60)=30\\ 
 f(4)=-\frac{1}{2} *(30)=-15\\ 
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2 years ago

Arrange the summation expressions in increasing order of their values.

dolphi86 [110]

∑ 4 * 5^(i-1) = 4 + 20 + 100 + 500 = 624
∑ 3 * 4^(i-1) = 3 + 12 + 48 + 192 + 768 = 1,023
∑ 5* 6^(i-1) = 5 + 30 = 35
∑ 5^(i-1) = 1 + 5 + 25 + 125 = 156
Answer:
∑ (i=1, 2) 5 * 6^(i-1) < ∑ (i=1, 4) 5^(i-1) < ∑ (i=1, 4) 4 * 5^(i-1) <
< ∑ (i=1, 5) 3 * 4^(i-1)

5 0

2 years ago

Read 2 more answers

Use the drawing tool(s) to form the correct answers on the provided graph.

NISA [10]

Answer:

2x– 3y = –18

3x + y = -5

Converting the equation in slope-intercept form

2x-3y= -18

-3y= -2x-18

-3y= -(2x+18)

3y=2x+18

y=(2x+18)/3

And for equation 2

y= -5-3x

For plotting the graph, the online graphing calculator desmos.com can be used.

The points can be calculated by putting negative and positive values of x in both equations.

The graph is attached as a picture.

As we can see from the graph that two lines intersect at (-3,4) so it is the solution of the given system of linear equations.

3 0

2 years ago

Read 2 more answers

Suppose that a disk drive has 5,000 cylinders, numbered 0 to 4,999. the drive is currently serving a request at cylinder 2,150,

Anni [7]

Answer:

13011, 7586, 7492 , 7424, 9917, and 9137.

Step-by-step explanation:

(1). FCFS is generally based on what is refer to as first come, first serve. That is to say the first one to come will be treated first so, we have that;

FCFS = 81 + 857 + 1084 + 504 + 2256 + 1074 + 1262 + 1167 + 3442 + 1284 = 13011.

(2). (SSTF) Is all about the shortest distance, for example in this question the shortest distance is =

Thus;

Total distance = (2150 - 2069) + (2296 - 2069) + ( 2296 - 2800) +( 3681 - 2800) + (4965 - 3681) + ( 4965 - 1618) + ( 1618-1523) + ( 1523-1212) + ( 1212-544) + ( 544 - 356).

=81 + 227 + 504 + 881 + 1284 + 3347 + 95 + 311 + 668 + 188 = 7586.

(3).SCAN deals with the processing of the nearest request

The distance =146 + 504 +881 + 1284 + 34(4999-4965) + 2930(4999-2069) + 451 + 95 + 311 + 668 +188 = 7492.

(4). LOOK is just like scan.

The distance = 146 + 504 + 881 + 1284 + 2896 + 451 + 95 + 311 + 668 + 188 = 7424.

(5). C-SCAN: this is the kind of scan from one end to the other.

The distance = 146 + 504 +881 +1284 + 34 (4999 - 4965) + 4999 (4999 -0 )+ 356 (356 -0 )+ 188 + 668 + 311 + 95 + 451 = 9917.

(6). C-LOOK : moves in the following order: 2150, 2296, 2800, 3681, 4965, here head moves back 356, 544, 1212, 1523, 1618, 2069.

Thus;

The distance = 146 + 504 + 881+ 1284 + 4609 (4965 - 356) + 188 + 668 + 311+ 95 + 451 = 9137.

4 0

2 years ago