Determine the mean and variance of the random variable with the following probability mass function. f(x)=(216/43)(1/6)x, x=1,2,3 Round your answers to three decimal places (e.g. 98.765).

Answers

Answer 1

Mean:

E[X] = ∑ x f(x) = 1 × f (1) + 2 × f (2) + 3 × f (3) = 51/43 ≈ 1.186

Variance:

Recall that for a random variable X, its variance is defined as

Var[X] = E[(X - E[X])²] = E[X ²] - E[X

Now,

E[X ²] = ∑ x ² f(x) = 1² × f (1) + 2² × f (2) + 3² × f (3) = 69/43

Then

Var[X] = 69/43 - (51/43)² = 366/1849 ≈ 0.198

(each sum is taken over x in the set {1, 2, 3})


Related Questions

Christian and Tanae both leave Disneyland at the same time. Christian travels north at 65 mph. Tanae travels south at 55 mph. How long will it take them to be 540 miles apart? Which of the following equations would you use to solve this word problem?
65t + 55(t − 1) = 540.
65t + 55t = 540.
65t + 55(t + 1) = 540.
None of these choices are correct.

Answers

Answer:

Step-by-step explanation:

B looks like it would work.

You add speeds * time when you are travelling in opposite directions.

I don't know why you would add or subtract 1 as in A and C

120 * t = 540

t = 540/120

t = 4.5 hours.

So after 4.5 hours they are 540 miles apart.

Answer:

b

Step-by-step explanation:

I need help on this question someone please help

Answers

Answer:

x > -2

Step-by-step explanation:

the graph stops at x = -2 and doesn't move further down

A construction company needs 2 weeks to construct a family room and
3 days to add a porch. Find the ratio of the time it takes for constructing the porch to the time constructing the family room, with all units in days.


Answers

Answer:

3/14

Step-by-step explanation:

it takes 3 days to construct a porch and 14 days to construct a family room

so porch/family room = 3/14

Brainliest if this was correct

​=
The solution set is
​ 1/2(10x+16)-13=-3/5(15x-35)

Answers

Answer: 13/7 or as a decimal 1.857142857

How did i get the answer:

Step 1: Simplify both sides of the equation.

so 1/2 of 10 is 5, 1/2 of 16 is 8

-3/5 of 15 is -9 and -3/5 of -35 is POSITIVE 21

all together should look like 5x+8+−13=−9x+21

(now we have to combine like terms)

8+ -13= -5

5x -5 = -9x+21

Step 2: Add 9x to both sides

5x + 9x= 14x

14x -5 = 21

Step 3: Add 5 to both sides.

21+5= 26

14x=26

Step 4: Divide both sides by 14.

26/14= 1.85714286 or 13/7

The solution is x= 13/7

salve by gauss jueabis method if iteration mothere aitration
4X+0.024x2-0.08x3=8
0.09x1+3x2-0.15x3=9
0.04x1+-0.08x2+4x3=20

Answers

I dunno g u got this tho

Suppose the composition of the 107th Senate is 45 Republicans, 50 Democrats, and 5 Independents. A new committee is being formed to study ways to benefit the arts in education. If 3 senators are selected at random to head the committee, find the probability of the following:
Part 1. The group of 3 consists of all Republicans.
Part 2. The group of 3 consists of all Democrats.
Part 3. The group of 3 consists of 1 from each party, including the Independent.

Answers

Answer:

1 : 0.088

2 : 0.12

3 : 0.07

Step-by-step explanation:

45 Rebullicans

50 Democrats

5 independents

Total = 100

Selection =  3

Part 1:

(45 C 3) / (100 C 3) = 0.088

Part 2:

(50 C 3) / (100 C 3) = 0.12

Part 3:

(45 C 1) x (50 C 1) x (5 C 1) / (100  C 3) = 0.07

Using a weight of 12 for the most recent observation, 13 for the second most recent observation, and 16 for third most recent observation, compute a three-week weighted moving average for the time series. (Round your answers to two decimal places.)

Answers

Answer: Hi some data is missing attached below is the missing data

answer:

WMA = 174.53

Step-by-step explanation:

Determine the three-week weighted moving average with weights

( 1/2, 1/3, 1/6 )

Weighted moving average ( WMA ) = 174.53

MSE = ∑ (xi - WMA)^2 / n

        = 9.71

attached below is the detailed solution/table

The width of a rectangular slab of concrete is 7 m less than the length. The area is 98 m squared. Find the dimensions

Answers

Answer:

Length = 14 m, Width = 7 m

Step-by-step explanation:

Let the length is l and width is b.

Width, b = l-7

Area of the rectangle, A = 98 m²

We know that, the area of a rectangle is as follow :

[tex]A=lb[/tex]

So,

[tex]98=l(l-7)\\\\98=l^2-7l\\\\l^2-7l-98=0\\\\l^2+7l-14l-98=0\\\\l(l+7)-14(l+7)=0\\\\l=14,-7[/tex]

Length can't be negative. So,

Width, b = 14-7 = 7 m

So, the dimensions of the rectangle are 14 m and 7 m respectively.

PLEASE I NEED SO MUCH HELP HERE!!!!!!

Answers

The answer is 1.5 I think

Which describes the transformations applied in the figure above?
1. A clockwise rotation of 180 degrees about the origin.

2. A counterclockwise rotation of 270 degrees about the origin.

3. A counterclockwise rotation of 90 degrees about the origin.

4. A clockwise rotation of 270 degrees about the origin.

Answers

Answer:

2. A counterclockwise rotation of 270 degrees about the origin.

Step-by-step explanation:

Point A before the transformation:

Before the transformation, point A was at (-2,2).

After the transformation, point A' is (2,2).

Point B:

Before the transformation, point B was at (-6,-3)

After the transformation, point B' is (-3,6).

Transformation rule:

From the transformations of points A and B, we get that the transformation rule is (x,y) -> (y,-x), which is a counterclockwise rotation of 270 degrees about the origin., and the correct answer is given by option 2.

A copy machine makes 44 copies per minute. How many copies does it make in 3 minutes and 45 seconds?

Answers

Answer:

in 3 minutes ;

44 × 3 = 132 copies

and 45 soconds;

[tex]45 \: seonds \: = \frac{3}{4} \: mınutes[/tex]

44 × ¾ = 33 copies

132 + 33 copies = 165 copies

HAVE A NİCE DAY

Step-by-step explanation:

GREETİNGS FROM TURKEY ツ


Now actually compute 2 - 8

Answers

Answer:

the answer is -6. you just subtract 2 with 8

write an equation in slope intercept form for the line with slope 1/4 and y-intercept -6.​

Answers

Answer:

y=¼x-6

Step-by-step explanation:

y=mx+c

y=¼x+-6

y=¼x-6

Y=1/4x-6 is the answer to your question.

Find the length of an arc that subtends a central angle of 224° in a circle of radius 20 m

Answers

Answer:

78.2m

Step-by-step explanation:

Lenght of the arc= ( circumference) × ( fraction of the circle)

Circumference=2πr = 2×20×π

Radius=20 m

fraction of the circle can be calculated as 224°/360°= 0.662

Then substitute the values we have

Lenght of the arc=

(2×20×π) ×0.662

= 78.2,

Lenght of the arc is 78.2m

75. In the figure below, what is the slope of
the diagonal AC of the rectangle ABCD?

Answers

9514 1404 393

Answer:

  A. 3/2

Step-by-step explanation:

Point C is 3 units higher and 2 units right of point A. The slope is ...

  slope = rise/run = 3/2


Algebraically show that each of the given combinations are equivalent to the given functions.
h(x) + j(x) is equivalent to k(x) given:

h(x) = 2x – 3;j(x) = - 4x + 6; k(x) = – 2x + 3

h(x) + j(2) =

Is h(x) + j(x) equivalent to k(x)? yes

Answers

Answer:

YES, they are equal

Step-by-step explanation:

Given the expressions

h(x) = 2x – 3;j(x) = - 4x + 6; k(x) = – 2x + 3

h(x) + j(x) = 2x – 3 + (-4x + 6)

h(x) + j(x) =  2x - 3 -4x + 6

h(x) + j(x) = 2x - 4x -3 + 6

h(x) + j(x) = -2x + 3 = k(x)

This shows that h(x) + j(x) =  k(x)

Suppose 44% of the children in a school are girls. If a sample of 727 children is selected, what is the probability that the sample proportion of girls will be greater than 41%

Answers

Answer:

0.9484 = 94.84% probability that the sample proportion of girls will be greater than 41%

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution

Problems of normal distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]

Suppose 44% of the children in a school are girls.

This means that [tex]p = 0.44[/tex]

Sample of 727 children

This means that [tex]n = 727[/tex]

Mean and standard deviation:

[tex]\mu = p = 0.44[/tex]

[tex]s = \sqrt{\frac{p(1-p)}{n}} = \sqrt{\frac{0.44*0.56}{727}} = 0.0184[/tex]

What is the probability that the sample proportion of girls will be greater than 41%?

This is 1 subtracted by the p-value of Z when X = 0.41. So

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

By the Central Limit Theorem

[tex]Z = \frac{X - \mu}{s}[/tex]

[tex]Z = \frac{0.41 - 0.44}{0.0184}[/tex]

[tex]Z = -1.63[/tex]

[tex]Z = -1.63[/tex] has a p-value of 0.0516

1 - 0.0516 = 0.9884

0.9484 = 94.84% probability that the sample proportion of girls will be greater than 41%

GIVING OUT BRAINLIEST IF GIVEN AN ANSWER WITH THOUROUGH EXPLANATION AND NOT JUST AN ANSWER! THANKS!

During the first part of a 6-hour trip, you travel 240 miles at an average speed of r miles per hour. For the next 72 miles of the trip, you
increase your speed by 10 miles per hour. What were
your two average speeds?

Answers

9514 1404 393

Answer:

50 mph for 4.8 hours60 mph for 1.2 hours

Step-by-step explanation:

One way to write the relationship between time, speed, and distance is ...

  time = distance/speed

For the first part of the trip, the time is ...

  t1 = 240/r

For the second part of the trip, the time is ...

  t2 = 72/(r+10)

The total time is 6 hours, so we have ...

  t1 +t2 = 6

  240/r +72/(r+10) = 6

We can simplify this a bit by multiplying by (r)(r+10)/6 to get ...

   40(r+10) +12(r) = r(r+10)

  r² -42r -400 = 0 . . . . . . . . subtract the left side and collect terms

  (r -50)(r +8) = 0 . . . . . . . . factor

  r = 50 . . . . . the positive solution of interest.

The two average speeds were 50 mph and 60 mph.

Rearrange 2x = y/w to make w the subject​

Answers

Yes i think that is the answer good boj

how many student have a grade lower than 80

Answers

Is this the whole question?

Step-by-step explanation:

Are you done typing or there's more to it.

Answer:

You look at your graph and or chart and start to make note

Your looking for the following tyoe data

1-5, 5-10  etc such distribution is usually done on y axes for histograms and x axes for all other graphs.

If there is a group data or frequency then you need to multiply the highest group data ie) from 0-5 it is 2.5

Then 2.5 times the actual frequency which is in the chart = say it says 4

Then 2.5 x 4 = 10

Then do the same for 5-10 = 7.5 midpoint

7.5 x frequency  of 2 = 15 and so on

Then 10-15 = 12.5 midpoint you show this by 10+15/2 = 12.5  frequency of 12.5 could be 6 as in example so 6 x 12.5 = 72  etc...

When you get all totals 10+ 15+ 72 in the fx bar you cna plot on graph and then see how many have a grade lower than 80

For histograms we dont do midpoint we do highest value then times it by frequency and so our grades for 0-5 = 5

and frequency is the number of students that got such mark so we do 5 x 4 = 20 and so on then divide this number by 5 again showing that 5 students got 5 or under

and keep adding these up, the reason we would need the fx totals ie) 20 for 0-5 is that you cna map it in a histogram by adding the number below it say its 0-5 = 5 and 5 x 4 = 20

but instead of doing separately thereafter 0-5 we just add the frequency amount to 20 so if its 5-10 = 10  then we get 10 x 2 = 20 and from 20 + 20 = 40

If no frequency was given we do 5 + 10 + 15 etc. until we get to our frequency that way.

Then after adding them all up we can use this amount to get our mean etc.

and to find how many are less than 80 if histograms boxes are shown we have to distribute from how many we know as total being first one 0-5 = 5 and count 5 into the box to see the frequency there.

Say the box is 25 little boxes we know then that 25/5 = 5 so the rate of frequency is 5 for each and that each box has the same frequency or the same distribution depending if frequency is shown a different way or not.

IF its box plot then the middle line is the median and you know its exactly half of frequency and can therafter work out quartiles and count down from 80 either using the given 79 number to the set start number at start of the whiskers.

Step-by-step explanation:

The mean incubation time of fertilized eggs is 19 days. Suppose the incubation times are approximately normally distributed with a standard deviation of 1 day. Answer the following. For each question draw an appropriate distribution function​ (graph) to represent the​ data, shade the desired area, and show all​ work, including what you input into your calculator to attain your results.
(A) The 14th percentile for incubation times is __ days.
(B) The incubation times that make up the middle 97% of fertilized eggs are __ to __ days.

Answers

Answer:

a)17.92

b) 16.83 .... 21.17

Step-by-step explanation:

ρ→   z

0.14 = -1.080319341

-1.080 = (x - 19)/1 = 17.92

~~~~~~~~~~~~~~~~~~

3% / 2 = 1.5%

1.5% - 98.5%

ρ→   z

0.015 = -2.170090378 ....  -2.17 = (x-19) =16.83

0.985 = 2.170090378  ....   2.17 = (x-19) =21.17

Write an expression for the sequence of operations described below.
double t, subtract v from the result, then subtract u from what you have
Do not simplify any part of the expression.

Answers

Step-by-step explanation:

Double t

t+t=2t

Subtract v

2t-v

Subtract u

2t-v-u

it is known that the population proton of utha residnet that are members of the church of jesus christ 0l6 suppose a random sample of 46 selceted and prioon of the sample that belongs to the churh is calcutated what is the problaity of obtaining a sample priton less than 0;50 g

Answers

Answer:

0.0838 = 8.38% probability of obtaining a sample proportion less than 0.5.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution

Problems of normal distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]

Proportion of 0.6

This means that [tex]p = 0.6[/tex]

Sample of 46

This means that [tex]n = 46[/tex]

Mean and standard deviation:

[tex]\mu = p = 0.6[/tex]

[tex]s = \sqrt{\frac{p(1-p)}{n}} = \sqrt{\frac{0.6*0.4}{46}} = 0.0722[/tex]

Probability of obtaining a sample proportion less than 0.5.

p-value of Z when X = 0.5. So

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

By the Central Limit Theorem

[tex]Z = \frac{X - \mu}{s}[/tex]

[tex]Z = \frac{0.5 - 0.6}{0.0722}[/tex]

[tex]Z = -1.38[/tex]

[tex]Z = -1.38[/tex] has a p-value of 0.0838

0.0838 = 8.38% probability of obtaining a sample proportion less than 0.5.

Compute ????×????, where ????=????−2????+5????, ????=2????+????+3????. (Write your solution using the standard basis vectors ????, ????, and ????. Use symbolic notation and fractions where needed.)

Answers

Given: ????=????−2????+5????

and ????=2????+????+3????

To find: We need to find the value of ????×????

Solution: Here given,

????=????−2????+5????

and ????=2????+????+3????

Therefore, solving these two we have, ????=0

So,????×????=0

I.- Sean los polinomios:
P(x) = 5x5 +4x3 –x +2 Q (X) = -3x4 -7x3 +9x -6 R(x) = 7x5 +3x2 + 8x -2
Halla:
1) P(X) + Q(X) 2) R (X) - P(X) 3) P(X) + R(X) - Q(X)
II.- Resuelve:
1) M= (x-1) (x-1) (x-1) - x3 +1

2) W= (x2 +x +1) (x2 -x +1)

Answers

Answer:

Step-by-step explanation:

M

If Joanne can paint a room in 3 hours and her sister Angela can paint the same room in 4 hours, how long (in h) would it take Joanne and Angela to paint the room working together? Round to the nearest tenth.

Answers

Answer:

Step-by-step explanation:

If J can paint a room in 3 hours, in 1 hour she gets [tex]\frac{1}{3}[/tex] of the job done.

If A can paint a room in 4 hours, in 1 hour she gets [tex]\frac{1}{4}[/tex] of the job done. We need to find out how long it takes them if they paint together. The equation for this is:

[tex]\frac{1}{3}+\frac{1}{4}=\frac{1}{x}[/tex] where x is the number of hours it takes them to get the job done together. Multiply everything through by 12x to get

4x + 3x = 12 so

7x = 12 and

x = 1.7 hours to get the room painted together.

Question 1 of 10
Estimate the difference of the decimals below by rounding to the nearest
whole number. Enter your answer in the space provided.
46.327
-4.801

Answers

Answer:

Step-by-step explanation:

46.327=46 ( neaarest whole number)

-4.801=-5 (nearest whole number)

46-(-5)=46+5=51

For this problem what I did was add all the measurements and I got 48 m. However, it is wrong. How do I go about solving the perimeter then?

Answers

9514 1404 393

Answer:

  66 m

Step-by-step explanation:

The perimeter is the sum of the measures of all of the sides. There are two side measures that are missing from the diagram.

The missing horizontal measure is ...

  17 m - 8 m = 9 m

The missing vertical measure is ...

  16m -7 m = 9 m.

If you add these to the sum you already calculated, you will get the correct answer:

  48 m + 9 m + 9 m = 66 m . . . perimeter of the figure

_____

If you're paying attention, you see that the sum of the measures of the two shorter horizontal segments is the same as the measure of the longer horizontal segment. Likewise, the sum of the measurements of the two shorter vertical segments is the same as that of the longer vertical segment.

In other words, the perimeter of this (and any) L-shaped figure is the same as the perimeter of a rectangle having the same horizontal and vertical dimensions as the long sides of the figure.

  P = 2(17 m +16 m) = 2(33 m) = 66 m

At noon, ship A is 150 km west of ship B. Ship A is sailing east at 30 km/h and ship B is sailing north at 25 km/h. How fast is the distance between the ships changing at 4:00 PM?

Answers

Answer:

At 4:00 PM the distance between the two ships is 104.40 kilometers.

Step-by-step explanation:

Given that at noon, ship A is 150 km west of ship B, and ship A is sailing east at 30 km / h and ship B is sailing north at 25 km / h, to determine how fast is the distance between the ships changing at 4:00 PM the following calculation must be performed:

150 - (30 x 4) = 150 - 120 = 30

0 + (25 x 4) = 0 + 100 = 100

30 ^ 2 + 100 ^ 2 = X ^ 2

√ (900 + 10,000) = X

√10,900 = X

104.40 = X

Therefore, at 4:00 PM the distance between the two ships is 104.40 kilometers.

amy shoots a 100 arrows at a target each arrow hits with a probability 0.01 what is the probability that one of her first 5 arrows hit the target

Answers

Answer:

0.5759

Step-by-step explanation:

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