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3 years ago

Why don't we measure spread about the mean by simply averaging x − x , the deviations of individual data values from their mean?

Mathematics

1 answer:

skad [1K]3 years ago

7 0

Answer:

Because this spread will add up to zero

Step-by-step explanation:

Mean defines the center of the data. Some values are below this center and some values are above this center.

For the values which are below the center (i.e. less than the mean), when mean is subtracted from these values, this results in negative numbers.

For the values which are above the center(i.e. greater than the mean), when mean is subtracted from these values, this results in positive numbers.

When these negative and positive numbers are summed together, as it is, they cancel out each other, leaving an answer equal to zero, which would be meaningless. As a spread of 0 would mean all data values are the same, when infact they aren't.

To avoid this, the difference of mean from the data value is squared, so that we can get all positive values, and then these values are added up together to calculate the spread of the data.

Conclusion:

The average of deviations of individual data from the mean will result in answer equal to zero, as a result they are squared first before finding the average.

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What number should go in the space multiplying by 1.44 is the same as increasing by.

Nuetrik [128]

Answer:

multiplying by 1.44 is the same as increasing by 44%

Step-by-step explanation:

this is because 44+100 divided by 100 is 1.44

6 0

2 years ago

Two ballpoint pens are selected at random from a box that contains 3 blue pens, 2 red pens, and 3 green pens. If X is the number

Flauer [41]

Answer:

a) f(x,y) = $\frac{\binom{3}{x}\binom{2}{y}\binom{3}{2-x-y}}{\binom{8}{2}}$ ; x = 0, 1 , 2; y = 0, 1 , 2; 0 ≤ x+y ≥ 2

b) = $\frac{9}{14}$

Step-by-step explanation:

joint probability is a function that characterizes the distribution of a random variable. If X and Y be two random variables then the joint probability will be P(X = x, Y=y)

Given Data,

X = The number of blue Pens

Y = The number of red Pens

possible outcomes(X, Y) are (0, 0), (0, 1), (1, 0), (1, 1), (0, 2), (2,0)

Please refer fig. also

total number ways of selecting any 2 pens = $\binom{8}{2}$ = $\frac{8!}{2! 6!}$ =28

f(x,y) = $\frac{\binom{3}{x}\binom{2}{y}\binom{3}{2-x-y}}{\binom{8}{2}}$ ; x = 0, 1 , 2; y = 0, 1 , 2; 0 ≤ x+y ≥ 2

P(X,Y)∈A = P(X + Y ≤ 1)

= P(0,0) + P(1,0) + P(0,1)

= $\frac{3}{28}$ + $\frac{3}{14}$ + $\frac{9}{28}$

= $\frac{9}{14}$

4 0

3 years ago

What is the simplified product of (2x)(x^2)+(2x)(x)+(2x)(-2)+(3)(x^2)+(3)(x)+(3)(-2)

NikAS [45]

(2x)(x^2)+(2x)(x)+(2x)(-2)+(3)(x^2)+(3)(x)+(3)(-2)

Simplifying

(2x)(x2) + (2x)(x) + (2x)(-2) + (3)(x2) + (3)(x) + (3)(-2)

Remove parenthesis around (2x)

2x(x2) + (2x)(x) + (2x)(-2) + (3)(x2) + (3)(x) + (3)(-2)

Multiply x * x2

2x3 + (2x)(x) + (2x)(-2) + (3)(x2) + (3)(x) + (3)(-2)

Remove parenthesis around (2x)

2x3 + 2x(x) + (2x)(-2) + (3)(x2) + (3)(x) + (3)(-2)

Multiply x * x

2x3 + 2x2 + (2x)(-2) + (3)(x2) + (3)(x) + (3)(-2)

Remove parenthesis around (2x)

2x3 + 2x2 + 2x(-2) + (3)(x2) + (3)(x) + (3)(-2)

Reorder the terms for easier multiplication:

2x3 + 2x2 + 2 * -2x + (3)(x2) + (3)(x) + (3)(-2)

Multiply 2 * -2

2x3 + 2x2 + -4x + (3)(x2) + (3)(x) + (3)(-2)

Multiply 3 * -2

2x3 + 2x2 + -4x + 3x2 + 3x + -6

Reorder the terms:

-6 + -4x + 3x + 2x2 + 3x2 + 2x3

Combine like terms: -4x + 3x = -1x

-6 + -1x + 2x2 + 3x2 + 2x3

Combine like terms: 2x2 + 3x2 = 5x2

-6 + -1x + 5x2 + 2x3

4 0

3 years ago

A stretch of highway that is 12 1/4 miles long has a speed limit signs every 7/8 of a mile. How many speed limit signs are on th

Maksim231197 [3]

Well 12 times four is 48 so you add 48 and 1 and the first fraction (12 1/4) becomes 49/4 then you multiply this by two so it becomes 98/8 now you can take 98 dived by 7 to make 14 speed limit signs on the highway

4 0

3 years ago

Read 2 more answers

Algebra help please?

konstantin123 [22]

Answer:

Instead of multiplying 3 * 5 Marjorie replaced x and made 35. Correct answer is 17

Step-by-step explanation:

3(5) + 2

15 + 2 = 17

4 0

3 years ago