A geologist has collected 5 specimens of basaltic rock and 7 specimens of granite. The geologist instructs a laboratory assistant to randomly select 9 of the specimens for analysis.
Let X= the number of granite specimens selected for analysis.
Note: Take 10 decimal places after the ".", if the answer is a fraction, enter the fraction (a/b). Use a period (.) not a comma (,) for decimals.
a) Compute EX = ?; Var(X) = ?
b) Compute P(X<6) = ?
c) What is the probability that all specimens of one of the two types of rock are selected for analysis?
P(all specimens of one of the two types of rock are selected for analysis) = ?

Answers

Answer 1

The rocks are chosen without replacement, which means that the hypergeometric distribution is used to solve this question. First we get the parameters, and then we answer the questions. From this, we get that:

[tex]E(X) = 5.25, Var(X) = 0.5966[/tex]P(X < 6) = 0.9545P(all specimens of one of the two types of rock are selected for analysis) = 0.2046.

Hypergeometric distribution:

The probability of x successes is given by the following formula:

[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}[/tex]

In which:

x is the number of successes.

N is the size of the population.

n is the size of the sample.

k is the total number of desired outcomes.

Combinations formula:

[tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

The mean and the variance are:

[tex]\mu = \frac{nk}{N}[/tex]

[tex]\sigma^2 = \frac{nk(N-k)(N-n)}{N^2(N-1)}[/tex]

We have that:

5 + 7 = 12 rocks, which means that [tex]N = 12[/tex]

9 are chosen, which means that [tex]n = 9[/tex]

7 are granite, which means that [tex]k = 7[/tex]

Question a:

[tex]E(X) = \mu = \frac{9\times7}{12} = 5.25[/tex]

[tex]Var(X) = \sigma^2 = \frac{9\times7(12-7)(12-9)}{12^2(12-1)} = 0.5966[/tex]

Thus:

[tex]E(X) = 5.25, Var(X) = 0.5966[/tex]

Question b:

Since there are only 5 specimens of basaltic rock, at least 9 - 5 = 4 specimens of granite are needed, which means that:

[tex]P(X < 6) = P(X = 4) + P(X = 5) + P(X = 6)[/tex]

In which

[tex]P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}[/tex]

[tex]P(X = 4) = h(4,12,9,7) = \frac{C_{7,4}*C_{5,5}}{C_{12,9}} = 0.1591[/tex]

[tex]P(X = 5) = h(5,12,9,7) = \frac{C_{7,5}*C_{5,4}}{C_{12,9}} = 0.4773[/tex]

[tex]P(X = 6) = h(6,12,9,7) = \frac{C_{7,6}*C_{5,3}}{C_{12,9}} = 0.3181[/tex]

Thus

[tex]P(X < 6) = P(X = 4) + P(X = 5) + P(X = 6) = 0.1591 + 0.4773 + 0.3181 = 0.9545[/tex]

So P(X < 6) = 0.9545.

Question c:

5 of basaltic and 4 of granite: 0.1591 probability.

7 of granite is P(X = 7), in which

[tex]P(X = 7) = h(7,12,9,7) = \frac{C_{7,7}*C_{5,2}}{C_{12,9}} = 0.0455[/tex]

0.1591 + 0.0455 = 0.2046, thus:

P(all specimens of one of the two types of rock are selected for analysis) = 0.2046.

A similar question is found at https://brainly.com/question/24008577


Related Questions

find the measure of the indicated angle

Answers

Answer:

Step-by-step explanation:

36°

gordan is twice as old as tony was when gordan was as old as tony is now. combined age of gordan and tony is 112 years. how old are gordan and tony now?​

Answers

gordan is 67 and Tony is 45 years old

Answer:

Answer

Tony:48

Gordan :64

Step-by-step explanation:

[tex]\begin{array}{c|c|c}Age&Gordon&Tony\\------------------&-------&-------\\now&g&t\\when\ gordan\ was\ as\ old\ as\ tony\ is\ now&t(=g-g+t)&t-g+t=2t-g\\\end{array}\\\\\\\\\left\{\begin{array}{ccc}g&=&2*(2t-g)\\g+t&=&112\\\end {array}\right.\\\\\\\left\{\begin{array}{ccc}3g&=&4t\\g+t&=&112\\\end {array}\right.\\\\\\\left\{\begin{array}{ccc}g&=&\dfrac{4}{3}\\\dfrac{7}{3} t&=&112\\\end {array}\right.\\\\\\\left\{\begin{array}{ccc}t&=&48\\g&=&64\\\end {array}\right.\\[/tex]

Proof:

16 years ago, Gordan was 48 and Tony 32.

64=2*32

64+48=112

for the vector (-9,3), find 1/2V, -V, and 4V

Answers

9514 1404 393

Answer:

1/2V = <-9/2, 3/2>-V = <9, -3>4V = <-36, 12>

Step-by-step explanation:

The scalar multiplier multiplies each of the components.

  1/2V = <-9×1/2, 3×1/2> = <-9/2, 3/2>

  -V = <(-9)(-1), (3)(-1)> = <9, -3>

  4V = <-9×4, 3×4> = <-36, 12>

Solve each equation for the given variable

1.3(2x+4)=54

2.4+(5x+5)54

Please

Answers

Answer:

1. x = 7

2. 270x+274

Explanation:

see attached filed for step by step reasoning

Answer:

1. x = 7

2. x = 9

Step-by-step explanation:

1. 3(2x + 4) = 54

Multiply 3 by the numbers in “( )”

6x + 12 = 54

Subtract 12 from both sides

6x = 42

x = 42/6

x = 7
****************************************
2. 4 + (5x + 5) = 54

Subtract 4 from both sides

5x + 5 = 50

Subtract 5 from both sides

5x = 45

x = 45/5

x = 9

Select the correct answer from each drop-down menu. Complete the statement. The solutions of sin2x= √3/2

are : 30 / 120 / 150 / 330

and

45 / 60 / 105 / 135

What are the correct solutions?

Answers

Answer:

henc X = 30°

Step-by-step explanation:

here is the proof

when X=30° then

sin2x = sin2×30

=sin 60°

= √3/2

or else,

putting value of X = 30° then

sin2x= 2sinxcosx

= 2×sin30°×cos30°

=2×1/2×√3/2

= 2√3/4

= √3/2

hence proved sin2x= √3/2.

The highest attendance at this stadium was in 2007 when 91,547 people attended. The average cost of a ticket was $57. How much money was made on ticket sales for that game?

Answers

Answer:57*91547

Step-by-step explanation:

What’s the distance between (4,-9) and (5,3)

Answers

Answer: Distance = √145

Concept:

Here, we need to know the concept of the distance formula.    

The distance formula is the formula, which is used to find the distance between any two points.

If you are still confused, please refer to the attachment below for a clear version of the formula.

Solve:

Given information

(x₁, y₁) = (4, -9)

(x₂, y₂) = (5, 3)

Given formula

[tex]Distance = \sqrt{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]

Substitute values into the formula

[tex]Distance = \sqrt{(5-4)^2+(3+9)^2}[/tex]

Simplify values in the parentheses

[tex]Distance = \sqrt{(1)^2+(12)^2}[/tex]

Simplify exponents

[tex]Distance = \sqrt{1+144}[/tex]

Simplify by addition

[tex]Distance = \sqrt{145}[/tex]

Hope this helps!! :)

Please let me know if you have any questions

Answer:

[tex]\boxed {\boxed {\sf \sqrt {145} \ or \ 12.04}}[/tex]

Step-by-step explanation:

The distance between 2 points is calculated using the following formula.

[tex]d= \sqrt {(x_2-x_1)^2+(y_2-y_1)^2)[/tex]

In this formula, (x₁, y₁) and (x₂, y₂) are the coordinates of the two points.

We know the two points are (4, -9) and (5,3). If we match the values of the points and the coordinating variable, we see that:

x₁ = 4y₁= -9 x₂ = 5 y₂ = 3

Substitute the values into the formula.

[tex]d= \sqrt { ( 5 -4)^2 + ( 3 --9)^2[/tex]

Solve inside the parentheses.

(5-4)= 1 (3 --9) = (3+9) = 12

[tex]d= \sqrt {(1)^2 + (12)^2}[/tex]

Solve the exponents.

(1)² = 1 *1 = 1 (12)² = 12 * 12 = 144

[tex]d= \sqrt{ 1+144}[/tex]

Add.

[tex]d= \sqrt{145[/tex]

Take the square root.

[tex]d=12.04159458[/tex]

Let's round to the nearest hundredth. The 1 in the thousandth place tells us to leave the 4 in the hundredth place.

[tex]d \approx 12.04[/tex]

The distance between the 2 points is √145 or approximately 12.04.

I need help with this question please

Answers

Answer:

Step-by-step explanation:

30t - 5t² = 10

5t² - 30t + 10 = 0

t = [30 ± √(30² - 4 ⋅ 5 ⋅ 10)] / [2 ⋅ 5]

= [30 ± √700] / 10

= [30 ± 10√7] / 10

= 3 ± √7

≈ 0.35 seconds and 5.65 seconds

5. Determine the formula for the following arithmetic sequence: 4, 7, 10, 13, ...

Answers

Answer:

[tex]a_{n}[/tex] = n + 3

Step-by-step explanation:

Each number increases by 3. Therefore, n+3.

Malika is 1.45 meters tall. At 10 a.m., she measures the length of a tree's shadow to be 32.25 meters. She stands 27.5 meters away from the tree, so that the tip of her shadow meets the tip of the tree's shadow. Find the height of the tree to the nearest hundredth of a meter.

Answers

Answer:

Step-by-step explanation:

If the length of a tree's shadow is 32.25 meters. The height of the tree to the nearest hundredth of a meter will be : 9.84m

Given:

Malika height=1.45 meters

Length =32.25 meters

Width =27.5 meters

Height of the tree=x

Proportion:

1.45 : 32.25 :: x : 27.5

Now let determine the height of the tree

32.25-27.5/1.45=32.25/x

4.75/1.45=32.25/x

Cross multiply

4.75x=32.25×1.45

4.75x=46.7625

Divide both side

x=46.7625/4.75

x=9.84m

Inconclusion  if the  length of a tree's shadow is 32.25 meters. The height of the tree to the nearest hundredth of a meter will be : 9.84m

Learn more here:

https://brainly.com/question/23966984

Solve each equation.
1) -133 = 7(-3 + 4v)

Answers

X=-4 trust me this right

Answer:

-4

Step-by-step explanation:

-133 = -21 + 28v

-133 + 21 = 28v

-112 = 28v

v = -4

What is the value of log,1252
PERE
3
5
Ο ΟΟΟ
15
Mark this and return
Save and Exit
Next

Answers

2 by 5 t get you 15k

look at the image for the question

Answers

Volume = l × b × h

Length = 7m

Breadth = 7m

Height = 9m

Volume = 7×7×9

441m³

Must click thanks and mark brainliest

*Will Give Brainliest* Find the length of side xx in simplest radical form with a rational denominator.

Answers

Answer:

10√2 = x

Step-by-step explanation:

Since the figure is a square, all angles of the square are equal to 90 degrees

The diagonal also bisects the 90 degrees into 2 45 degrees

So you can use special triangles to find x

Ratio of sides of a 45-45-90 triangle is 1: 1: √2

10: 10: 10√2

you can also use pythagorean theorem

10^2 + 10^2 = x^2

100 + 100 = x^2

200 = x^2

10√2 = x

Answer:

12

Step-by-step explanation:

12=12

IM DOING THIS TO GIVE OTHER GUY BRAINLIEST CUZ HE ALSO HELPED ME GET IT RIGHT

PLEASE HELP!! WHOEVER HELPS FIRST AND GETS IT CORRECT GETS BRAILIEST!!

Answers

Answer:

16 rotations

Step-by-step explanation:

500/32 = 15.625

15.625 rounded = 16

hope it helps!

Need help answer plz help

Answers

Answer:

BONANA MY NANA

Step-by-step explanation:

Approximately how many times greater is
7.4 x 10^8
than
2.5 x 10^7
0.3
3
30
300

Answers

Answer:

30

Step-by-step explanation:

To compare the numbers, divide the first number by the second number.

(7.4 x 10^8)/(2.5 x 10^7) = (74 x 10^7)/(2.5 x 10^7) = 74/2.5 = 29.6

Answer: 30

7.4 x 10^8= 740000000
2.5 x 10^7: 25000000

Answers If You Use The Other Numbers
x0.3= 7500000
x3= 75000000
x30= 750000000
x300= 7500000000

Answer: Not Possible

If You Did 7.5 x 10^8 it will make more sense but you didn’t so the answer is unspecified.

Which polynomial expressions are in standard form?
x2 - x - 72
(x + 3)(x - 7)
-8x + 56
05
5x(2x)

Answers

ANSWER: -8x + 56

Standard Form Equation: y=mx+b

Answer:

PLATO ANSWER

Step-by-step explanation:

x2 − x − 72

-8x + 56

5

those are the correct answers

rewrite the following statements into algebraic expression
the sum of x and y
5 is subtracted from y​

Answers

x+y

5-y

i really hope this is it.

How to calculate pvalue

Answers

Answer:

If your test statistic is positive, first find the probability that Z is greater than your test statistic (look up your test statistic on the Z-table, find its corresponding probability, and subtract it from one). Then double this result to get the p-value.

Answer:

The p-value is calculated using the sampling distribution of the test statistic under the null hypothesis, the sample data, and the type of test being done (lower-tailed test, upper-tailed test, or two-sided test). The p-value for: a lower-tailed test is specified by: p-value = P(TS ts | H 0 is true) = cdf(ts)

Step-by-step explanation:

May this answer is helpful for you

Find a formula for a function f that satisfies the following conditions. lim x→±∞ f(x) = 0,   lim x→0 f(x) = −∞,  f(2) = 0 lim x→7− f(x) = ∞,   lim x→7+ f(x) = −∞​

Answers

9514 1404 393

Answer:

  f(x) = (x -2)/(x²(7-x))

Step-by-step explanation:

The horizontal asymptotes of zero mean the denominator degree needs to be greater than the numerator degree. The zero at x=2 means (x-2) will be a factor in the numerator. The limit at x=0 means there will be a factor of x² in the denominator. Since the numerator term is negative at x=0, the signs of the terms so far do not need modification.

The vertical asymptote at x=7 means there will be a factor of (x-7) in the denominator. In order for the limits to be correct, it must have a negative sign:

  -(x -7) = (7 -x)

Then the function with these characteristics can be written ...

  f(x) = (x -2)/(x²(7 -x))

A rectangular prism has volume 1,088 ft3 and height 8 ft. What is the area of the base of the prism?
a. 146 ft2
c. 136 ft2
b. 1,080 ft2
d. 1,096 ft2​

Answers

Height=8ftVolume=1083ft^3

We know

[tex]\boxed{\sf Volume=Area\:of\:Base\times Height}[/tex]

[tex]\\ \sf\longmapsto Area\:of\:Base=\dfrac{Volume}{Height}[/tex]

[tex]\\ \sf\longmapsto Area\:of\:Base=\dfrac{1088}{8}[/tex]

[tex]\\ \sf\longmapsto Area\;of\:base=136ft^2[/tex]

Devaughn is 6 years older than Sydney. The sum of their ages is 56 . What is Sydney's age?

Answers

Answer:

Devaughn = 31, Sydney = 25

Step-by-step explanation:

(56-6)÷2= 25

So they would both be 25 if they were the same age but Devaughn is 6 years older so 25+6=31

Age of Sydney=xAge of Devaghn=x+6

ATQ

[tex]\\ \sf\longmapsto x+x+6=56[/tex]

[tex]\\ \sf\longmapsto 2x+6=56[/tex]

[tex]\\ \sf\longmapsto 2x=56-6[/tex]

[tex]\\ \sf\longmapsto 2x=50[/tex]

[tex]\\ \sf\longmapsto x=\dfrac{50}{2}[/tex]

[tex]\\ \sf\longmapsto x=25[/tex]

What’s the answer to this?

Answers

Answer:

[tex]f(3x)=9x^2-3[/tex]

Step-by-step explanation:

One is given the following function:

[tex]f(x)=x^2-3[/tex]

One is asked to evaluate the function for ([tex]f(3x)[/tex]). Substitute ([tex]3x[/tex]) in place of ([tex]x[/tex]) then simplify. Remember that a number raised to an exponent is the same as that number times itself the number of times that the exponent indicates. One can apply this logic here while simplifying,

[tex]f(x)=x^2-3[/tex]

[tex]f(3x)=(3x)^2-3[/tex]

[tex]f(3x)=(3x*3x)-3[/tex]

[tex]f(3x)=(9x^2)-3[/tex]

[tex]f(3x)=9x^2-3[/tex]

Which of the following is an example of a sample that would NOT be random?

A. Going through the list and choosing the first 25 names on the list.
B. Writing each student’s name on a card and then drawing out 25 names without looking.
C. Choosing one student at random from the list and going through the list and choosing every fifth student until she has 25 names.
D. Separating the students on the list into boys and girls and choosing a sample from each group that is proportional to the size of the group.

Answers

Answer: D

"Separating the students on the list into boys and girls and choosing a sample from each group that is proportional to the size of the group."

Step-by-step explanation:

You are sampling an equal amount of boys and girls since your getting an equal sample of each gender. (Not random)

The option that is not a random sample is:

Separating the students on the list into boys and girls and choosing a sample from each group that is proportional to the size of the group.

Option D is the correct answer.

What is random sampling?

It is the way of choosing a number of required items from a population given.

Each item has an equal probability of being chosen.

We have,

We will see which option is a sample that is not random.

A. Going through the list and choosing the first 25 names on the list.

Going through the list means every name has an equal chance of getting chosen.

This is a random sample.

B. Writing each student’s name on a card and then drawing out 25 names without looking.

Since we are drawing out 25 names without looking, all the students' names have an equal chance of getting drawn.

This is a random sample.

C. Choosing one student at random from the list and going through the list and choosing every fifth student until she has 25 names.

Choosing one student at random means every student has an equal chance of getting chosen.

This is a random sampling.

D. Separating the students on the list into boys and girls and choosing a sample from each group that is proportional to the size of the group.

The students are separated into boys and girls and the sample is chosen from each group so we are selecting the sample from the separated group.

This can not be a random sampling.

Thus,

The option that is not a random sample is:

Separating the students on the list into boys and girls and choosing a sample from each group that is proportional to the size of the group.

Option D is the correct answer.

Learn more about random sampling here:

https://brainly.com/question/12719656

#SPJ2

A/An is a type of blood cell that's also called a red blood cell. a) Jeukocyte O b) thrombocyte c) plasma d) erythrocyte

Answers

Answer:

opt. (d)

Step-by-step explanation:

red blood cell, also called erythrocyte, cellular component of blood, millions of which in the circulation of vertebrates give the blood its characteristic colour and carry oxygen from the lungs to the tissues.

What is the conjugate of 3 + 6i?
A -3 - 61
B 3 - 6i
C 3 + 6i
D 9i

Answers

Answer:

C.3-6

Step-by-step explanation:

Every complex number has a complex conjugate.

Examples is a+bi the conjugate is a-bi,if your adding the two conjugate its going to be 2a and if your subtracting the result is 2bi.And if multiplied it is seen as complex number which are a²+b²

The sum of a number and its inverse is 3 29 / 52. Find the number?​

Answers

What does the inverse mean in this scenario

Mila wants to buy a scooter for Rs 62,000 . She has only Rs 19,000 with her, so she decides to take a loan from a bank for the remaining amount. The bank offers Mini three loan schemes as shown below. Mini has to return the loan amount with interest in equal monthly instalments


1) How much money does mila take as loan from the bank?

a) Rs 62,000
b) Rs 44,000
c) Rs 45,000
d) Rs 43,000​

Answers

Answer:

Scheme a 45000 is the answer

Answer is D Rs.43,000I hope this answer may be right

12/1,000 into decimal​

Answers

0.012 is the answer!

I hope this helps you out! :D

[tex]\\ \sf\longmapsto \dfrac{12}{1000}[/tex]

1000 has 3zeros hence decimal will go 3 points left

[tex]\\ \sf\longmapsto 0.012[/tex]

More:-

[tex]\\ \sf\longmapsto \dfrac{1}{10}=0.1[/tex]

[tex]\\ \sf\longmapsto \dfrac{1}{100}=0.01[/tex]

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