Coliform bacteria are randomly distributed in a river at an average concentration of 1 per 20cc of water. What is the variance of the number of Coliform bacteria in a sample of 40cc of water

Answers

Answer 1

Answer:

[tex]Var = 1.9[/tex]

Step-by-step explanation:

Given

[tex]p = \frac{1}{20}[/tex]  i.e. 1 per 20cc of water

[tex]n = 40[/tex] -- sample size

Required

The variance

This is calculated using:

[tex]Var = np(1 - p)[/tex]

So, we have:

[tex]Var = 40 * \frac{1}{20} * (1 - \frac{1}{20})[/tex]

[tex]Var = 40 * \frac{1}{20} * \frac{19}{20}[/tex]

[tex]Var = 2 * \frac{19}{20}[/tex]

[tex]Var = \frac{38}{20}[/tex]

[tex]Var = 1.9[/tex]


Related Questions

Identify the transformation that occurs to create the graph of h(x).
H(x)=f(x+3)

Answers

Answer: The graph moved left 3 units.

(x, y) = (x - 3, y)

How would I draw the reflection over the line y=2x+5?

Answers

Answer:

Step-by-step explanation:

Solve the system of equations using the elimination method 5x+10y = 3
10x + 20y = 8

Answers

Answer:

No solution

Step-by-step explanation:

5x+10y=3 equation 1

10x+20y=8 equation 2

-2(5x+10y)=-2(3) multiply equation 1 by -2 to eliminate x

-10x-20y=-6 equation 1 multiplied by -2

10x+20y=8 equation 2

0  +  0  =2. Add above equations

    0      =2  

no solution

Follow the process of completing the square
to solve 2x2 + 8x - 12 = 0.
After adding B2 to both sides of the equation in step 4, what is the constant on the right side of the equation?

Answers

2x^2 + 8x - 12 = 0..divide by 2

x^2 + 4x - 6 = 0

x^2 + 4x = 6...add 4 to both sides of the equation

x^2 + 4x + 4 = 6 + 4

(x + 2)^2 = 10....<== ur constant is 10

x + 2 = (+-)sqrt 10

x = -2 (+ - ) sqrt 10

x = -2 + sqrt 10

x = -2 - sqrt 10

In a family of 3 children, what is the probability that there will be exactly 2 boys assuming that the sexes are equally likely to occur in each birth​

Answers

Answer:

There is a 60.00 percent probability of a particular outcome and 40.00 percent probability of another outcome.

For a particular species of wolf, 55% are female, 20% hunt in medium-sized packs, and 15% are both female and hunt in medium-sized packs. What is the percent of wolves that are female but do not hunt in medium-sized packs?

Answers

20% is the answer
55%-20%-15%=20%

The radius of a sphere is increasing at a rate of 2 mm/s. How fast is the volume increasing (in mm3/s) when the diameter is 60 mm?

Answers

Answer:

22608 mm³/s

Step-by-step explanation:

Applying chain rule,

dV/dt = (dV/dr)(dr/dt)............... Equation 1

Where dV/dr = rate at which the volume is increasing

But,

V = 4πr³/3

Therefore,

dV/dr = 4πr²............... Equation 2

Substitute equation 2 into equation 1

dV/dt = 4πr²(dr/dt).............. Equation 3

From the question,

Given: dr/dt = 2 mm/s, r = 60/2 = 30 mm

Consatant: π = 3.14

Substitute these values into equation 3

dV/dt = 4×3.14×30²×2

dV/dt = 22608 mm³/s

Simplify. v80

A. 16v5
B. 5v4
C. 4v5
D. 20v4

Answers

Hi!

√80 = √(16 • 5) = √(4² • 5) = 45

In a test of a heat-seeking rocket, a first rocket is launched at 2000 fts and the heat-seeking rocket is launched along the same flight path 20 s later at a speed of 3000 fts. Find
the timest, and t, of flight of the rockets until the heat-seeking rocket destroys the first rocket
What are the times of the flight?

Answers

Answer:

Time of flight of first rocket = 60 seconds

Time of flight of second rocket = 40 seconds

Step-by-step explanation:

Let the time of flight of first rocket be t1.

Since the second rocket is launched 20 seconds later, then it means that;

t1 = t2 + 20

Where t2 is the time of flight of the second rocket.

When destruction has occurred, it means that both of the rockets would have covered the same distance.

We know that;

Distance = speed × time

Thus;

2000t1 = 3000t2

We know that t1 = t2 + 20

Thus;

2000(t2 + 20) = 3000t2

2000t2 + 40000 = 3000t2

3000t2 - 2000t2 = 40000

1000t2 = 40000

t2 = 40000/1000

t2 = 40 seconds

Thus;

t1 = 40 + 20

t1 = 60 seconds

A Line passes through the .4 -6 and has a slope of -3 and four which is the equation of the line

Answers

Answer:

(in the image)

Step-by-step explanation:

I'm not sure I understood your question completely but I hope this helps.

Please answer & number. Thank you! <33

Answers

Answer:

2)=2

4)=3

5)=5

8)=-1

Step-by-step explanation:

just divide the number by the number with variable

Probabilityyyyyyyyyyyyyyy

Answers

Answer:

Reduce if needed, asked or necessary

Step-by-step explanation:

1. 4/10

2. 2/6

3. 4/10

4. more likely

Answer:

Since Probability Is Usually Written In Fraction Form OR Ratios

(Although It Really Doesn't Matter):

1.  4/10 (2/5)

2.  2/6  (1/3)

3.  6/10 (3/5)

(All Fraction Form)

Last Question:

I can't really see the bottom but probably its 'More likely' since you can already see a bunch of red marbles.

Step-by-step explanation:

This is the basic fraction form :  ____ / ____

Based on what they ask, like the probability of picking out a black marble, count the number of black marbles in the particular bag and put that number as the numerator. The denominator is the total amount of marbles in that particular bag. Hope this helps!

You have to find the value of k

Answers

Answer:

115

Step-by-step explanation:

By converting to an exponential expression, solve log2 (x + 5) = 4

Answers

Step-by-step explanation:

just insert a base of two at on both sides and solve.

The solution of the logarithmic equation ㏒ (x + 5) / ㏒ 2 = 4 will be 11.

What is the solution to the equation?

The allocation of weights to the important variables that produce the calculation's optimum is referred to as a direct consequence.

The logarithmic equation is given below.

㏒₂(x + 5) = 4

Simplify the equation, then we have

㏒ (x + 5) / ㏒ 2 = 4

㏒ (x + 5) = 4 × ㏒ 2

㏒ (x + 5) = ㏒ 2⁴

Take antilog on both sides, then we have

(x + 5) = 2⁴

(x + 5) = 16

x = 11

The solution of the logarithmic equation ㏒ (x + 5) / ㏒ 2 = 4 will be 11.

More about the solution of the equation link is given below.

https://brainly.com/question/545403

#SPJ2

I need help with this.

Answers

Answer:

A and b Are in quadrant 2. F and D are in quadrant 1. F is in quadrant 3 and C is in quadrant 4

Step-by-step explanation:

each quadrant is in the boxes and the question is asking what is each  coordinate is in what quadrant

Create a circle such that its center is point A and B is a point on the circle.

Answers

Answer:

The center of a circle is the point in the circle which is equidistant to all the edges of thr circle. The point a is the center, while point b is an arbitrary point in the circle. Find attachment for the diagram.

Which of the following consists of discrete​ data?
A. Number of suitcases on a plane.
B. Amount of rainfall.
C. Hair color.
D. Tree height.

Answers

Answer:

A

Step-by-step explanation:

Number of suitcases on a plane is discrete because you can only have an integer amount. You can't have a fraction of a suitcase on a plane.

sets A and B have 3 and 6 elements respectively. what can be the minimum number of elements in AUB

Answers

Answer:

6

Step-by-step explanation:

n(AUB) = n(A) + n(B) - n(AnB)

n(AUB) can have the minimum number of elements if n(AnB) has the maximum number of elements.

n(AnB) maximum = 3

so n(AUB) = 3+6-3 = 6

i need helpp pleaseee

Answers

To plot the point (3,-7) start at the origin (0,0) and move right three (3) units and then down seven (7) units.

Suppose that you are interested in determining the average height of a person in a large city. You begin by collecting the heights of a random sample of 196 people from the city. The average height of your sample is 68 inches, while the standard deviation of the heights in your sample is 7 inches. The standard error of your estimate of the average height in the city is

Answers

Answer:

The standard error of your estimate of the average height in the city is 0.5 inches.

Step-by-step explanation:

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.

You begin by collecting the heights of a random sample of 196 people from the city.

This means that [tex]n = 196[/tex]

The standard deviation of the heights in your sample is 7 inches.

This means that [tex]\sigma = 7[/tex]

The standard error of your estimate of the average height in the city is

[tex]s = \frac{\sigma}{\sqrt{n}} = \frac{7}{\sqrt{196}} = 0.5[/tex]

The standard error of your estimate of the average height in the city is 0.5 inches.

if side of square is 4.05 find its area ​

Answers

Answer:

A

16.4

please give brain list

Need help with this really fast

Answers

Answer:

6

Step-by-step explanation:

You can apply the proportion of 9/6 to 4 to get 6:

6*(9/6)= 9

So

4*(9/6) = Length LA

6= Length LA

Answer:

Option C, or [tex]2\frac{2}{3}[/tex]

Explanation:

We can see that the Line FM in the smaller triangle dialates to Line LK in the bigger triangle by the scale factor of:

FM/LK

6/9 or 2/3

So we would know that to find out the value of LA in the bigger triangle we would have to dialate it’s corresponding side FI in the smaller triangle by the same scale factor:

4 * 2/3

=> [tex]2\frac{2}{3}[/tex] = LA

Hope this helps!

The original price of a set lunch was 30 dollars. It is now sold at a 20%
discount. There is an extra discount of 10% for students. How much
should a student pay to order a set lunch?

Answers

Find out the total discount percentage that students receive.

20% + 10% = 30%

30/100 x 30 = 9 dollars

30 - 9 = 21 dollars (Final answer)
20% of $30 = $6
30 - 6 = $24
10% of $24 = $2.40
24 - 2.40 = $21.60 cost of student lunch

You have to do each percent separate to get the cost.
If you just take 30% off from the original cost of $30 it will be the wrong answer.

A manufacturer is interested in the output voltage of a power supply used in a PC. Output voltage is assumed to be normally distributed, with standard deviation 0.25 volt, and the manufacturer wishes to test volts against volts, using units. In your intermediate calculations, use z-scores rounded to two decimal places (e.g. 98.76).
(a) The acceptance region is_____. Find the value of a.
(b) Find the power of the test for detecting a true mean output voltage of 5.1 volts.

Answers

Answer: hello your question was poorly written but i was able to the get missing parts online which enabled me resolve your question

answer:

a) a = 0.1096

b) 1.89 watts

Step-by-step explanation:

Std of output voltage = 0.25 volt

H0 : μ = 5 volts

Ha : μ ≠ 5 volts

n = 16

a) Acceptance region = 4.9 ≤ X ≤ 5.1  

Determine the value of a

value of a = 0.0548 + 0.0548

                 = 0.1096

attached below is the reaming solution

note : a is a type 1 error

b) power of test

True mean output voltage = 5.1 volts

P = - 1.89 watts

power cant be negative hence the power of the test  = 1.89 watts

On Monday, 27 adults visited an amusement park. On Tuesday, 23 adults visited the amusement park. The enterance fee for the adults is Rs. 100. How much amount is collected from the adults in these two days?

PLEASE TELL FULL SOLUTION. ​

Answers

Answer:

5000

Step-by-step explanation:

Add the number of adults first: 27+23=50

Then multiply the number of adults by 100 for the fee.

50*100 = 5000

Answer:

within the two days a total of 5000$ where collected in the two days

Solution:

R= 100 per adult

1 adult = 100

27(R)+ 23(R) = 27(100)+ 23(100)

27(100)+23(100) =5000

or add both 27 and 23 and multiple by 100

50•100 = 5000

F(x) =-2x-4 find x if f(x)=14

Answers

Answer:

14=-2x-4

18=-2x

x=-9

Hope This Helps!!!

is there a formula for this?
help asap!!

Answers

Answer:

yes

Step-by-step explanation:

the answer is c well thats what my teacher said

Answer:

B

Step-by-step explanation:

using sine rule

[tex] \frac{y}{sin \: 45} = \frac{5}{sin \: 45} \\ y = 5[/tex]

using sin rule

[tex] \frac{x}{sin \: 90} = \frac{5}{sin \: 45} \\ \\ 5sin90 = xsin45 \\ \\ x = \frac{5 \: sin \: 90}{sin \: 45} \\ x = \frac{5}{0.7071} \\ x = 7.071[/tex]

x=5√2

i need help solving this .

Answers

Answer:b

Step-by-step explanation:

Answer:

just be smart trust me u dont need us to give u the answer ur super smart

Step-by-step explanation:

make me brainliest to help people be encourage

Assume that the breaking system of a train consists of two components connected in series with both of them following Weibull distributions. For the first component the shape parameter is 2.1 and the characteristic life is 100,000 breaking events. For the second component the shape parameter is 1.8 and characteristic life of 80,000. Find the reliability of the system after 2,000 breaking events:

Answers

Answer:

0.9984

Step-by-step explanation:

we have shape parameter for the first component as 2.1

characteristics life = 100000

for this component

we have

exp(-2000/100000)².¹

= e^-0.0002705

= 0.9997

for the second component

shape parameter = 1.8

characteristic life = 80000

= exp(-2000/80000)¹.⁸

= e^-0.001307

= 0.9987

the reliability oif the system after 2000  events

= 0.9987 * 0.9997

= 0.9984

if cosA=3√2/5,then show that cos2A=11/25

Answers

Answer:

Step-by-step explanation:

Cos 2A = 2Cos² A - 1

             [tex]= 2*(\frac{3\sqrt{2}}{5})^{2}-1\\\\=2*(\frac{3^{2}*(\sqrt{2})^{2}}{5^{2}})-1\\\\=2*\frac{9*2}{25} - 1\\\\=\frac{36}{25}-1\\\\=\frac{36}{25}-\frac{25}{25}\\\\=\frac{11}{25}[/tex]

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