A box of 10 flashbulbs contains defective . A random sample of 2 is selected and tested. Let X be the random variable associated with the number of defective bulbs in the sample. a. Find the probability distribution of X. b. Find the expected number of defective bulbs in a sample.

Answers

Answer 1

Answer:

(a)

[tex]Pr(x = 0) = \frac{^7C_2}{45}[/tex]            [tex]Pr(x = 1) = \frac{^7C_1 * ^3C_1}{45}[/tex]            [tex]Pr(x = 2) = \frac{^3C_2}{45}[/tex]

(b)

[tex]E(x) = \frac{3}{5}[/tex]

Step-by-step explanation:

Given

[tex]n = 10[/tex] --- flashbulbs

[tex]k = 3[/tex] --- defective bulbs

[tex]r = 2[/tex] --- selected

Solving (a): The distribution of x

The total outcome is: [tex]^nC_r[/tex]

This gives:

[tex]^{10}C_2 = 45[/tex]

Having 3 defective bulbs means 7 are not.

When there is no defective bulb among the selected, the probability is:

[tex]Pr(x = 0) = \frac{^7C_2}{45}[/tex]

When 1 is defective:

[tex]Pr(x = 1) = \frac{^7C_1 * ^3C_2}{45}[/tex]

When both are defective

[tex]Pr(x = 2) = \frac{^3C_2}{45}[/tex]

So, the distribution is:

[tex]Pr(x = 0) = \frac{^7C_2}{45}[/tex]

[tex]Pr(x = 1) = \frac{^7C_1 * ^3C_1}{45}[/tex]

[tex]Pr(x = 2) = \frac{^3C_2}{45}[/tex]

Solving (b): The expected value

This is calculated as:

[tex]E(x) = \sum x * Pr(x)[/tex]

So, we have:

[tex]E(x) = x_1 * Pr(x_1) +x_2 * Pr(x_2) + ............... + x_n * Pr(x_n)[/tex]

The equation becomes:

[tex]E(x) = 0* Pr(x=0) +1* Pr(x=1) + 2 * Pr(x=2)[/tex]

[tex]E(x) = 1* Pr(x=1) + 2 * Pr(x=2)[/tex]

[tex]E(x) = Pr(x=1) + 2 * Pr(x=2)[/tex]

From the distribution in (a), we have:

[tex]E(x) = \frac{^7C_1 * ^3C_1}{45} + 2 * \frac{^3C_2}{45}[/tex]

[tex]E(x) = \frac{7 * 3}{45} + 2 * \frac{3}{45}[/tex]

[tex]E(x) = \frac{21}{45} + \frac{6}{45}[/tex]

[tex]E(x) = \frac{21+6}{45}[/tex]

[tex]E(x) = \frac{27}{45}[/tex]

Simplify

[tex]E(x) = \frac{3}{5}[/tex]


Related Questions

Compare the two linear functions listed below and determine which has a negative slope.

Answers

Answer:

Gift card

Step-by-step explanation:

Given

Function 1 and 2

Required

Which has a negative slope

For the first function (Gift card), we have the following observation.

As x increases from 0, 1, 2 and then 3

The values of y keep reducing

This means that the gift card function has a negative slope

For the second function (calculator rental)

We have:

[tex]c = 10 + 5m[/tex]

The slope of function [tex]y =mx + b[/tex] is m

So, by comparison

[tex]m=5[/tex]

5 is positive,

This means that the gift card function has a negative slope

Change 10 miles per hour to meters per second (hint: you'll need to
change from miles to kilometers, then change kilometers to meters)


how do i do this work shown!!

Answers

Answer:

10 miles per hour = 0.1862 meter per second

Step-by-step explanation:

Given

Speed in miles per hour = 10 miles per hour

As we know

1 mile = 1609.34 meters

and 1 hour  = 24*60 *60 seconds

Thus, 10 miles per hour in meter per second would be

10 * 1609.34/24*60 *60

= 0.1862 meter per second

Dina invests $600 for 5 years at a rate of 2% per year compound interest.
Calculate the value of this investment at the end of the 5 years,

Answers

Answer:

The investment after 5 years is $ 662.45.

Step-by-step explanation:

Principal, P = $ 600

Time, t = 5 years

Rate of interest, R = 2 %

Time , t = 5 years

The amount after the time 5 years is

[tex]A = P \times \left ( 1+\frac{R}{100} \right )^t\\\\A = 600\left ( 1+0.02 \right )^5\\\\A = 662.45[/tex]

So, the investment after 5 years is $ 662.45.

emergency helpn please i dk wut they mean

Answers

Answer:

below

Step-by-step explanation:

that is the procedure above

ABCD is a kite, find the value of y

Answers

Answer:

All triangles add to 180 degrees.  

180 = 90 + 40 + angle ABX

angle ABX = 180 - 90 - 40

Angle y = 50

Step-by-step explanation:

All triangles add up to 180 degrees.

A computer professor is interested in studying the amount of time it would take students enrolled in the Introduction to Computers course to write and run a program in Matlab. The professor hires you to analyze the following results in minutes from a random sample of 9 students:

10 12 8 16 12 13 10 11 15

Required:
At the 0.05 level of significance, is there evidence that the population average time is greater than 10 minutes?

Answers

Answer:

Following are the solution to the given question:

Step-by-step explanation:

In this question, firstly we calculating the [tex]\bar{x} \ \ and \ \ s[/tex]

[tex]\bar{x}=11.89 \\\\s = 2.52\\\\n = 9\\\\\alpha=0.05\\[/tex]

[tex]H_0 : u \leq 10\\\\ H_1 : u > 10[/tex]

It is an upper test  and testing the statistics:

[tex]t=\frac{\bar{x}-\mu }{\frac{s}{\sqrt{n}}}\\\\t=\frac{11.89-10 }{\frac{2.52}{\sqrt{9}}}\\\\t=2.25\\\\[/tex]

So, the test statistics [tex]t=2.25[/tex]

[tex]\alpha=0.05 \\\\ d.f = n-1\\\\[/tex]

     [tex]=9-1\\\\=8[/tex]

critical value =2.306 ( using t-table ) [tex]critical\ value >\ test\ statistics , \ Fail\ to\ Reject\ H_0[/tex]

Decision: We should not reject the null hypothesis.

What is the distance between the points (4.10) and (-3,-14) on the coordinates plane?

Answers

Answer:

25 units

Step-by-step explanation:

use the distance formula to get the square root of 24² + 7²

this will give you the square root of 625, which is 25

You measure 20 turtles' weights, and find they have a mean weight of 45 ounces. Assume the population standard deviation is 11.5 ounces. Based on this, what is the maximal margin of error associated with a 90% confidence interval for the true population mean turtle weight. Give your answer as a decimal, to two places

Answers

Answer: the maximal margin of error associated with a 90% confidence interval for the true population mean turtle weight = 4.23

Step-by-step explanation:

Formula for margin of error : [tex]E=\dfrac{z^*\times (Population\ standard\ deviation)}{\sqrt{Sample\ size}}[/tex]

, where z* = Critical z-value.

Given: population standard deviation = 11.5 ounces

Sample size = 20

Z value for 90% confidence level = 1.645

margin of error (E) = [tex]\dfrac{1.645\times11.5}{\sqrt{20}}[/tex]

[tex]\approx4.23[/tex]

Hence, the maximal margin of error associated with a 90% confidence interval for the true population mean turtle weight = 4.23

Which expression is equivalent to 3/4x -1/4xy

Answers

Answer:

\frac{3+x\frac{-4}{4xy}}{4x}

4x

3+x  

4xy

−4

 

 

Step-by-step explanation:


What is x3 – 25x factored completely

Answers

Answer:

x(x2-25)=o

x=0;x=5 and -5

Answer:

[tex] {x}^{3} - 25x \\ = x( {x}^{2} - {5}^{2} ) \\ = x(x - 5)(x + 5)[/tex]

Can someone help me solve this

Answers

Answer:

[tex]y = {(x + 8)}^{3} - 9[/tex]

Need help will give brainliest

Answers

Answer:

X=15

Step-by-step explanation:

line segment with length 18 is tangent and other one is secant so

[tex] {18}^{2} = 12(12 + x) \\ 324 = 144 + 12x \\ 324 - 144 = 12x \\ 180 = 12x \\ x = 180 \div 12 \\ x = 15[/tex]

The vertex of the parabola below is at the point (2, -5). Which of the equations
below could be the one for this parabola?

Answers

The one that is equations is 2

Is this answer correct? If not, which one is correct?

Answers

Answer:

correct

Step-by-step explanation:

Write the prime factorization of 4

Answers

Answer:

2 x 2

Explanation:

The prime numbers that multiply to 4 are 2 and 2.

2 x 2 hope this helps

A study followed for 10 years a sample of 82,695 middle-aged men with no prior history of heart failure living in California. The daily number of minutes spent being sedentary (seated) was recorded in diaries and reported on regularly administered questionnaires. During the course of the study, a total of 3,473 men experienced heart failures. Participants with high sedentary time and low sedentary times were compared. The proportion experiencing a heart failure was higher in the group of men spending more time being sedentary.
This study is an example of:_________
a. longitudinal cohort study
b. case-control observational study
c. voluntary response sample or anecdotal data
d. completely randomized experiment
e. matched pairs / repeated measures experiment
f. cross-sectional sample survey
g. census (population data)

Answers

Answer:

f. cross-sectional sample survey

Step-by-step explanation:

- longitudinal cohort study is when the group of subjects that comprises the cohort is chosen based on a disease or injury and is then monitored over time at routine intervals. In this question, it's not the case as the sample of men were just picked and studied with no special group or cohort.

- If it was case-control observational study, the research would have started with identifying those who have heart failure and those who don't have heart failure but it wasn't the case and thus this is not correct.

- If this was voluntary response sample, it means the men would have been self chosen which means they volunteered to be part of the study if it was of interest to them. But this is not the case here.

- If it was completely randomized experiment, it means that the people sampled would have been randomly assigned to different treatments which was not so in this question.

- If it were to be match pairs experiment, it means the men sampled would be grouped into pairs and each pair will be assigned different treatments which didn't happen in this question.

- If it were to be cross-sectional sample survey, it means that data will be collected from a population of interest to make inferences from that population at a point in time. That is the case here because data about sedentary time or less was taken and compared to know the effect it had on heart failure.

- If it were census, it will just be about getting the size of the population without making inquiries about sedentary time.

A: A
B: B
C: C
D: D

Show work!

Answers

Answer: A

Step-by-step explanation:

Area of a triangle is base times height

We have a base made by point m and n with a length of 6

now the third point has to form a height which when put with the base, gets you 18

area of triangle is bh/2

so lets set height as h, 6x/2 = 18 6x = 36 x = 6

This means the point has to be 6 apart either left or right. Only point that matches this is a.

If 25x2 – 35x – 18 is written as a2 – 7a – 18, what is a in terms of x?
a =

Answers

Answer:

a = 5x

Step-by-step explanation:

The value of an in terms of x will be a = 5x.

What is an expression?

The mathematical expression combines numerical variables and operations denoted by addition, subtraction, multiplication, and division signs.

Mathematical symbols can be used to represent numbers (constants), variables, operations, functions, brackets, punctuation, and grouping. They can also denote the logical syntax's operation order and other properties.

Given that the expressions are  25x² – 35x – 18 is written as a² – 7a – 18.

The value of an in terms of x will be calculated as:-

25x² – 35x – 18

a² – 7a – 18.

Compare the first term of the two equations,

25x² = a²

a = √25x²

a = 5x

To know more about an expression follow

https://brainly.com/question/20724072

#SPJ2

Which type of sequence is shown? -2, 0, 2, 4, 6, . . .

Answers

Answer:

The type of sequence that is show is an arithmetic sequence

Step-by-step explanation:

The lines below are perpendicular. If the slope of the green line is -1/6, what is the slope of the red line?

Answers

If the slope of the green line is −¹/₆ and the red line is perpendicular to the green line, then the slope for red line is the negative inverse of the green line. Therefore, the slope of the red line is 6.

Answer:

slope of red line=6

Step-by-step explanation:

Hi there!

We're given a set of perpendicular lines and the slope of the green line being -1/6

Perpendicular lines have slopes that are negative and reciprocal; if they are multiplied together, the result is -1

So to find the slope of the red line, we can use this formula (m is the slope):

-1/6m=-1

Multiply both sides by -6 (clears the fraction to get 1m on the left)

m=6

So the slope of the red line is 6

Hope this helps!

annual survey in which readers rate their favorite cruise ship. All ships are rated on a -point scale, with higher values indicating better service. A sample of ships that carry fewer than passengers resulted in an average rating of , and a sample of ships that carry or more passengers provided an average rating of . Assume that the population standard deviation is for ships that carry fewer than passengers and for ships that carry or more passengers. Round your all answers to two decimal places.

Answers

This question is incomplete, the complete question is;

Condé Nast Traveler conducts an annual survey in which readers rate their favorite cruise ship. All ships are rated on a 100-point scale, with higher values indicating better service.

A sample of 37 ships that carry fewer than 500 passengers resulted in an average rating of 85.36, and a sample of 44 ships that carry 500 or more passengers provided an average rating of 81.40.

Assume that the population standard deviation is 4.55 for ships that carry fewer than 500 passengers and 3.97 for ships that carry 500 or more passengers. What is the value of the test statistic? Round your all answers to two decimal places.

Answer:

value of the test statistic is 4.13

Step-by-step explanation:

Given the data in the question;

fewer than 500 passengers                           more than 500 passengers

n₁ = 37                                                               n₂ = 44

x'₁ = 85.36                                                         x'₂ = 81.40

s₁ = 4.55                                                            s₂ = 3.97

Now, to get the test statistics, we use the following formula;

z = (x'₁ - x'₂) / √( [tex]\frac{s_1^2}{n_1} + \frac{s_2^2}{n_2}[/tex] )

we substitute

z = ( 85.36 - 81.40 ) / √( [tex]\frac{(4.55)^2}{37} + \frac{(3.97)^2}{44}[/tex] )

z = 3.96 / √( [tex]\frac{20.7025}{37} + \frac{15.7609}{44}[/tex] )

z = 3.96 / √( 0.5595 + 0.3582 )

z = 3.96 / √0.9177

z = 3.96 / 0.957966596

z = 4.1337 ≈ 4.13

Therefore, value of the test statistic is 4.13

Josh's annual salary is $39.000. A total of $12.330.96 will be deducted for taxes and health insurance. He will receive his paycheck monthly in 12 equal installments. How much will he get paid with each paycheck?

Answers

Answer:

Step-by-step explanation:

without tax and insurance deduction- 3,250 (monthly)

with tax and insurance deduction-26,669.04/12=2,222.42 (monthly)

Need help in understanding how to solve this problem.

>> Find an equation of the plane through (−2,3,2) and parallel to the plane 3x+y+z= 4

Answers

Answer:

Step-by-step explanation:

3x+y+z= 4

3x+ y = 4 - z

y = 4-z-3x

We then make parallel

y-2 = 4−z−3x

y-2 = 4-2 -z-3x

y-2 = 2-z-3x

y = -z-3x+2

factorise a2-17a+42

Answers

Answer:

(a-14) (a-3)

Step-by-step explanation:

Answer:

(a - 14) (a - 3)

Step-by-step explanation:

a² - 3a - 14 a + 42

a(a - 3) - 14 ( a - 3)

(a - 14) (a - 3)

7. Your closet has 10 shirts for every 4 sweaters. Your closet has 40 shirts. How many sweaters are
in your closet?

Answers

Answer:

16 sweaters

Step-by-step explanation:

4=10

4=10

4=10

4=10

4x4=16

which of the following us the graph of f(x)=-0.5| x+3| -2

Answers

I think the answer is y=−0.5|x+3|−2
put the equation into a desmos graphing calculator and it’ll give you the graph!!

A 12 SIDED DIE WITH SIIDES LABLELED 1-12 ARE ROLLED ONCE. EACH NUMBER IS LIKELY TO BE ROLLED .WHAT IS THE PROBABILITY OF ROLLING A NUMBER GREATER THAN 10

Answers

Answer:

p=.1666

11 or 12

2 out of 12

2/12

1/6

p=.1666

Step-by-step explanation:

On a coordinate plane, rhombus W X Y Z is shown. Point W is at (7, 2), point X is at (5, negative 1), point Y is at (3, 2), and point Z is at (5, 5).
What is the perimeter of rhombus WXYZ?

Answers

the answer is 4,13 of the perimeter

(x+iy)^4 -(x+iy)^2 +16=0

Answers

Answer:

below

Step-by-step explanation:

that is the procedure above

Please help me no links

Answers

Answer:

c

Step-by-step explanation:

The graph starts at 100 and decreases as it goes the following situations that were listed should be somewhat implying that something is decreasing. Since a and b are GAINING something then it can't be that because it is increasing, so we are left with choice c.

hope this helps!

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