2. How to find the variance and standard deviation of a discrete
random variable?​

Answers

Answer 1

Answer:

To find the variance just take the second moment and subtract that from the first moment squared

To find the standard deviation just take the square root of the variance

Step-by-step explanation:


Related Questions

Write down in terms of n, an expression for the nth term
of the following sequences:
a) 6 2 -2 -6 -10
b) -8 -15 -22 -29 -36

Answers

Answer:

[tex]{ \bf{(a).}} \\ { \tt{ {n}^{th} = a + (n - 1)d }} \\ { \tt{ {n}^{th} = 6 + (n - 1) \times - 4 }} \\ {n}^{th} = 10 - 4n \\ \\ { \bf{(b).}} \\ { \tt{ {n}^{th} = - 8 + (n- 1) \times - 7 }} \\ { \tt{ {n}^{th} = -1 - 7n}}[/tex]

If 5(y-2) - 3(y + 4) = 0, then y
IS
A. -1
B. 3
C. 7
D. 11​

Answers

Answer:

Y is -1.

Step-by-step explanation:

If you substitute the values, you find that that's the correct answer.

11 because you distribute the 5 to y and -2 and distribute the -3 to y and 4 so it would be (5y-10) and (-3y-12) combine like terms which would end in 2y and -22 set up as 2y=-22 and solve getting 11

Which phrases can be represented by the algebraic expression 2x + 1? Check all that apply.
two times a number plus 1
a number plus 2
twice a number and one
two more than a number and one
twice the product of a number added to 1

Answers

Twice the product of a number added to 1
Two times a number plus 1
Twice a number and one

Which is an x-intercept of the continuous function in the
table?
-2
-1
0
1
2
3
f(x)
-10
48
46
44
-2
0
(0, -6)
(3.0)
O (-6.0)
(0, 3)

Answers

Answer:

The x-intercept is the value of the variable x when the value of the function is equal to zero

so

In the table we have

(-1, 0)(−1,0) is a x-intercept, because

For x=-1x=−1 the value of the function is equal to zero

(-6, 0)(−6,0) is a x-intercept, because

For x=-6x=−6 the value of the function is equal to zero

therefore

the answer is

the continuous function in the table has two x-intercepts

(-1, 0)(−1,0)

(-6, 0)(−6,0)

Use the limit definition of the derivative to find the instantaneous rate of change of
f(x)=5x^2+3x+3 at x=4

Answers

[tex]f'(4) = 43[/tex]

Explanation:

Given: [tex]f(x)=5x^2 + 3x + 3[/tex]

[tex]\displaystyle f'(x)= \lim_{h \to 0} \dfrac{f(x+h) - f(x)}{h}[/tex]

Note that

[tex]f(x+h) = 5(x+h)^2 + 3(x+h) + 3[/tex]

[tex]\:\:\;\:\:\:\:= 5(x^2 + 2hx + h^2) + 3x + 3h +3[/tex]

[tex]\:\:\;\:\:\:\:= 5x^2 + 10hx + 5h^2 + 3x + 3h +3[/tex]

Substituting the above equation into the expression for f'(x), we can then write f'(x) as

[tex]\displaystyle f'(x) = \lim_{h \to 0} \dfrac{10hx + 3h + 5h^2}{h}[/tex]

[tex]\displaystyle\:\:\;\:\:\:\:= \lim_{h \to 0} (10x +3 +5h)[/tex]

[tex]\:\:\;\:\:\:\:= 10x + 3[/tex]

Therefore,

[tex]f'(4) = 10(4) + 3 = 43[/tex]

What is the product of the rational expressions shown below? Make sure your
answer is in reduced form. X+1/x-4 • 5x/x+1?

Answers

Answer:

5x / (x - 4)

Step-by-step explanation:

(x + 1)/(x - 4) • 5x/(x + 1)

Method 1:

Cancel out x + 1

Leaving 5x/(x - 4)

Method 2:

(x + 1)/(x - 4) • 5x/(x + 1)

Multiply numerator and denominator separately

= 5x(x + 1) / (x - 4)(x + 1)

Cancel out (x + 1) in the numerator and (x + 1) in the denominator

= 5x / (x - 4)

Therefore,

(x + 1)/(x - 4) • 5x/(x + 1) = 5x / (x - 4)

Five times the sum of a number and 27 is greater than or equal to six times the sum of that number and 26. What is
the solution set of this problem?
0 (-0, -21)
O (-0, -21]
o [-21, +00)
O (21, +00)

Answers

Answer:

5 × (x + 27) ≥ 6 × (x + 26).

Step-by-step explanation:

The solution set of " Five times the sum of a number and 27 is greater than or equal to six times the sum of that number and 26" is (-∞, -21]

What is a solution set to an inequality or an equation?

If the equation or inequality contains variable terms, then there might be some values of those variables for which that equation or inequality might be true. Such values are called solution to that equation or inequality. Set of such values is called solution set to the considered equation or inequality.

For this case, let the number in consideration be 'x', then according to the condition specified, we get:

The sum of a number and 27 = x+27Five times the sum of a number and 27 = [tex]5(x+27)[/tex]The sum of that number and 26  = x + 26Six times the sum of that number and 26 = [tex]6(x+26)[/tex]

Also, we get:

Five times the sum of a number and 27 is greater than or equal to six times the sum of that number and 26 as:

[tex]5(x+27) \geq 6(x+26)[/tex]

Expanding and taking x on one side:

[tex]5x+135 \geq 6x+156\\135-156 \geq x \\\\x \leq -21[/tex]

Thus, the considered statement is true for all the numbers which is smaller or equal to -21. Symbolically, the solution set is: (-∞, -21]

The square bracket shows that the -21 is included in the interval. And the interval  (-∞, -21] is  set of all real numbers smaller or equal to -21.

Thus, the solution set of " Five times the sum of a number and 27 is greater than or equal to six times the sum of that number and 26" is (-∞, -21]

Learn more about inequalities here:

https://brainly.com/question/27425770

find the equation of line parallel to y=-2x+1 and passing through the point (2,4)

Answers

Answer:

[tex]y=-2x+8[/tex]

Step-by-step explanation:

Hi there!

What we need to know:

Linear equations are typically organized in slope-intercept form: [tex]y=mx+b[/tex] where m is the slope and b is the y-intercept (the value of y when x is 0)Parallel lines always have the same slopes

1) Determine the slope (m)

[tex]y=-2x+1[/tex]

The given line has a slope of -2. Because parallel lines always have equal slopes, we know that the line parallel to this would also have a slope of -2. Plug this into [tex]y=mx+b[/tex]:

[tex]y=-2x+b[/tex]

2) Determine the y-intercept (b)

[tex]y=-2x+b[/tex]

Plug in the given point (2,4) to solve for b

[tex]4=-2(2)+b\\4=-4+b[/tex]

Add 4 to both sides to isolate b

[tex]4+4=-4+b+4\\8=b[/tex]

Therefore, the y-intercept of the line is 8. Plug this back into [tex]y=-2x+b[/tex]:

[tex]y=-2x+8[/tex]

I hope this helps!

factor x^2-8x-48 completely

Answers

Answer: (X-12)(x+4)

The middle number is -8 and the last number is -48.

Factoring means we want something like

(x+_)(x+_)

Which numbers go in the blanks?

We need two numbers that...

Add together to get -8

Multiply together to get -48

Can you think of the two numbers?

Try 4 and -12:

4+-12 = -8

4*-12 = -48

Fill in the blanks in

(x+_)(x+_)

with 4 and -12 to get...

(x+4)(x-12)

Answer:

(x+4)(x−12)

[tex]\implies {\blue {\boxed {\boxed {\purple {\sf { (x - 12)(x + 4 )}}}}}}[/tex]

[tex]\large\mathfrak{{\pmb{\underline{\red{Step-by-step\:explanation}}{\red{:}}}}}[/tex]

[tex] {x}^{2} - 8x - 48[/tex]

[tex] = {x}^{2} + 4x - 12x - 48[/tex]

Taking [tex]x[/tex] as common from first two terms and [tex]12[/tex] from last two terms, we have

[tex] = x \: (x + 4) - 12 \: (x + 4)[/tex]

Taking the factor [tex](x+4)[/tex] as common,

[tex] = (x - 12)(x + 4)[/tex]

[tex]\large\mathfrak{{\pmb{\underline{\orange{Mystique35 }}{\orange{❦}}}}}[/tex]

Identify the level of measurement of the​ data, and explain what is wrong with the given calculation. In a​ survey, the favorite sports of respondents are identified as 1 for basketball, 2 for baseball, 3 for football, and 4 for anything else. The average​ (mean) is calculated for 517 respondents and the result is 1.5.

Answers

Answer:

(a) Nominal data

(b) Calculating the mean is wrong

Step-by-step explanation:

Given

[tex]1 \to[/tex] Basketball

[tex]2 \to[/tex] Baseball

[tex]3 \to[/tex] Football

[tex]4 \to[/tex] Others

Solving (a): The level of measurement

In the given parameters, digit 1 to 4 are used to label each of the given sport.

When such labels are used, the type of data is nominal.

Solving (b): The error

In (a), we identified that the level of measurement is nominal. This implies that, the data are not counted, but instead they are categorized.

And as such, the mean of the data cannot be calculated.

In a recent year, 31.6% of all registered doctors were female. If there were 53,000 female registered doctors that year, what was the total number of registered doctors?

Answers

Answer:

The total number of registered doctors was 167,722.

Step-by-step explanation:

Total number of doctors:

The total number of doctors is given by x.

31.6% of all registered doctors were female. 53,000 female doctors.

This means that:

[tex]0.316x = 53000[/tex]

What was the total number of registered doctors?

We have to solve the above equation for x. So

[tex]x = \frac{53000}{0.316}[/tex]

[tex]x = 167722[/tex]

The total number of registered doctors was 167,722.

Complete each congruency statement and name the rule used. If you cannot show the triangles are congruent from the given information, leave the triangle's name blank and write CNBD for "Cannot be determined" in place of the rule. ∆ARE ≅ ∆_____ by _____

Answers

Answer:

add a picture so i can see .

Step-by-step explanation:

On a
paper, graph y < -2x Then determine which answer matches
the graph you drew.

Answers

Answer:

theres the graph

Step-by-step explanation:

PLEASE HELP ASAP!!!
Describe the graph of the function g by transformations of the base function f.
(Graph and Answers pictured!)

Answers

Answer:

Option (3)

Step-by-step explanation:

Base function in the graph is 'f' and the transformed form of the function 'f' is function 'g'.

Since, the base function 'f' is reflected across the x-axis,

h(x) = -f(x)

Followed by the translation by 3 units downwards,

g(x) = h(x) - 3

      = -f(x) - 3

Therefore, function in the form of g(x) = -f(x) - 3 will be the answer.

Option (3) is the correct option.

Answer the following questions using what you've learned from this unit. Write your
answers in the space provided. Be sure to show all work.
CLASSIFY and MEASURE TRIANGLES
1. Find angle measures and use angles to classify triangles.
Part I: Find the missing angle measure in each triangle. Show your work.
(3 points, 1 point each)
AAN
50"
В
A
mC
m B
mA

Answers

Answer:

50"

В

A

mC

m B

mA

Step-by-step explanation:

An employer has a staff of eighty actuaries, ten of whom are student actuaries. A student actuary is allowed a total of ten weeks off per year (52 weeks in a year) for studying, vacation, and sick days. A non-student actuary is given four weeks off a year. It is assumed that all actuaries use all of the weeks off allocated to them. The actuary Mr. Taylor is at work today. What is the probability that he is a student?

Answers

Answer:

0.1111

Step-by-step explanation:

From the given information;

Number of staffs in the actuary = 80

Out of the 80, 10 are students.

i.e.

P(student actuary) = 10/80 = 0.125

number of weeks in a year = 52

off time per year = 10/52 = 0.1923

P(at work || student actuary) = (50 -10/52)

= 42/52

= 0.8077

P(non student actuary) = (80 -10)/80

= 70 / 80

= 0.875

For a non-student, they are only eligible to 4 weeks off in a year

i.e.

P(at work | non student) = (52-4)/52

= 48/52

= 0.9231

P(at work) = P(student actuary) × P(at work || student actuary) + P(non student actuary) × P(at work || non studnet actuary)

P(at work) =  (0.125 × 0.8077) + ( 0.875 × 0.9231)

P(at work) = 0.1009625 + 0.8077125

P(at work) = 0.90868

Finally, the P(he is a student) = (P(student actuary) × P(at work || student actuary) ) ÷ P(at work)

P(he is a student) = (0.125 × 0.8077) ÷ 0.90868

P(he is a student) = 0.1009625 ÷ 0.90868

P(he is a student) = 0.1111

Find the area of the composite area

Answers

Area of rectangle = LxW = 13x7 = 91

Area of triangle = bxh/2 = 7x7/2= 24.5

Total area= 91+24.5= 115.5 in^2

Julie borrowed 3500 for 3years at a seven and a half simple interest rate how much interest rate is that​

Answers

Answer:

787.50

Step-by-step explanation:

interest=3500*7.5*3/100

interest=35*7.5*3

interest=787.50

13 multiplied by the sum of 4 and11. Now reverse the result and add it to the earliest result and then multiplied it by 13​

Answers

Step-by-step explanation:

I am not critically certain but the ways you have jotted down your enquiry..

I assume is

13 × (4×11)

13 × 44

=572 - 44= 528

528+13 =541

541 ×13=7033

What is the mean absolute deviation of Warren’s data?
Warren's Scores Absolute Deviation from Mean Score – individual score
0
25
15
10
20
30
10
15
5
25
20
15
20
5
10
sum of absolute deviations =

Answers

Answer:

6.667

Step-by-step explanation:

I just did the calculations

I am not sure how to approach this problem or where to start? How would I be able to solve this problem?

Answers

Answer:

5.7

Step-by-step explanation:

We can use a proportion to solve the problem:

24 : 100 = 1.37 : x

x = (100 * 1.37)/24 = 137/24 = 5.7

Which of the following will have 6 at unit place?  a.19² b.11² c.24² d.13²​

Answers

i wanna say the answer is c)24^2

A true false test contains 24 questions. In how many different ways can this test be completed. (Assume we
don't care about our scores.)

Answers

Answer:

The total number of ways to give the answer of the question is 16777216.

Step-by-step explanation:

Total number of questions = 24

The number of possibilities so that the answer is given is only 2. It is either true or false.

So, the total number of ways to complete the test is

[tex]2^{24} = 16777216[/tex]

If the length of a rectangle is four times its width and the perimeter of the rectangle is 90 yd, whats its area?

Answers

Answer:

324 yds ^2

Step-by-step explanation:

If length=l and width=w, you could write an equation to find the length and width. Then use that to find the area. L=4w. There are two of each side in the rectangle. 4w+4w+w+w=10w. 10w=90. w=9. 4w=36. L=36. 36*9=324yds^2

Calculate the sample standard deviation and sample variance for the following frequency distribution of heart rates for a sample of American adults. If necessary, round to one more decimal place than the largest number of decimal places given in the data.

Lower Bound Upper Bound Frequency
56 64 11
65 73 15
74 82 14
83 91 4
92 100 11

Required:
a. What is the sample standard deviation?
b. What is the sample variance?

Answers

Answer:

[tex]\sigma = 12.5[/tex] ---- sample standard deviation

[tex]\sigma^2 = 157.2[/tex] ---- sample variance

Step-by-step explanation:

Solving (a): The sample variance

First, we calculate the midpoint of each class (this is the average of the limits)

So, we have:

[tex]x_1 = \frac{56 + 64}{2} = 60[/tex]

[tex]x_2 = \frac{65 + 73}{2} = 69[/tex]

And so on

So, the table becomes:

[tex]\begin{array}{cc}{x} & {f} & {60} & {11} & {69} & {15} & {78} & {14} & {87} & {4} & {96} & 11 \ \end{array}[/tex]

Calculate the mean

[tex]\bar x = \frac{\sum fx}{\sum f}[/tex]

[tex]\bar x = \frac{60*11+69*15+78*14+87*4+96*11}{11+15+14+4+11}[/tex]

[tex]\bar x = \frac{4191}{55}[/tex]

[tex]\bar x = 76.2[/tex]

The variance is:

[tex]\sigma^2 = \frac{\sum f(x - \bar x)^2}{\sum f - 1}[/tex]

So, we have:

[tex]\sigma^2 = \frac{(60 - 76.2)^2*11+(69 - 76.2)^2*15+(78 - 76.2)^2 *14+(87 - 76.2)^2*4+(96 - 76.2)^2*11}{11+15+14+4+11-1}[/tex]

[tex]\sigma^2 = \frac{8488.8}{54}[/tex]

[tex]\sigma^2 = 157.2[/tex]

The sample standard deviation is:

[tex]\sigma = \sqrt{\sigma^2[/tex]

[tex]\sigma = \sqrt{157.2[/tex]

[tex]\sigma = 12.5[/tex]

Solving (b): The sample variance

In (a), we calculate the sample variance to be:

[tex]\sigma^2 = 157.2[/tex]

c+12<16
what will be the answer

Answers

Answer:

[tex]c < 4[/tex]

Step-by-step explanation:

Move the constant to the right-hand side and change its signs:

[tex]c < 16 - 12[/tex]

Subtract the numbers:

[tex]c < 16 - 12 = c < 4[/tex]

Am I correct? If not which of the answers is correct?

Answers

Answer:

Yea you are right.

Step-by-step explanation:

х
f(x)
What is the initial value of the exponential function
represented by the table?
-2
1
8
e
8
-1
1
4
0
1
2
1
1
1
2
2
2

Answers

Answer:

the answer will be table -1

Step-by-step explanation:

please help. question in picture ​

Answers

Answer:

Step-by-step explanation:

hi pls help me now i'll gibe you brainest,thank you​

Answers

Answer:

64 cm^3

Step-by-step explanation:

answer for question no 5

length , breadth and height of the cube are always equal .So

here length = 4 cm

volume of a cube = l^3

=4^3

=64 m^2

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