Suppose that 1% of the employees of a certain company use illegal drugs. This company performs random drug tests that return positive results 99% of the time if the person is a drug user. However, it also has a 2% false positive rate. The results of the drug test are known to be independent from test to test for a given person.

a) Steve, an employee at the company, has a positive test. What is the probability that he is a drug user?

b) Knowing he failed his first test, what is the probability that Steve will fail his next drug test?

c) Steve just failed his second drug test. Now, what is the probability that he is a drug user?

Answers

Answer 1

Answer:

a) Pr(drug user| positive test) = 0.3333

b) The probability that he will failed his first test = 0.9703

c) the probability that he is a drug user since  failed his second drug test

= 0.961165

Step-by-step explanation:

From the given information:

Suppose that 1% of the employees of a certain company use illegal drugs.

Probability of illegal drug user = 0.01

Probability of user that do not use drug = 1 - 0.01 = 0.99

From the person that is a illegal drug user, the company performs random drug tests that return positive results = 0.99

Therefore, the negative result for illegal drug user = 1 - 0.99 = 0.01

However, it also has a 2% false positive rate.

i.e the probability of the user that do not use drug has a positive result of 2% = 0.02

Thus, the probability of the user that do not use drug has a negative result of = 1 - 0.02

= 0.98

We are tasked to answer the following questions.

a) Steve, an employee at the company, has a positive test. What is the probability that he is a drug user?

i.e This employee we are taking about is a drug user and he has a positive test.

Thus;

Pr(drug user| positive test) = [tex]\dfrac{0.99 \times 0.01}{0.99 \times 0.01+ 0.02 \times 0.99}[/tex]

Pr(drug user| positive test) = [tex]\dfrac{0.0099}{0.0099+0.0198}[/tex]

Pr(drug user| positive test) = [tex]\dfrac{0.0099}{0.0297}[/tex]

Pr(drug user| positive test) = 0.3333

b) Knowing he failed his first test, what is the probability that Steve will fail his next drug test?

The probability that he will failed his first test = ((0.01 × 0.01) + (0.99×0.98))

The probability that he will failed his first test = ( 1 × 10⁻⁴ + 0.9702)

The probability that he will failed his first test = 0.9703

c)  Steve just failed his second drug test. Now, what is the probability that he is a drug user?

the probability that he is a drug user since he  failed his second drug test using Bayes theorem can be expressed as:

= [tex]\dfrac{0.01 \times(0.99\times 0.99)}{0.01 \times (0.99 \times0.99)+ 0.99(0.02 \times0.02)}[/tex]

the probability that he is a drug user since failed his second drug test

= [tex]\dfrac{0.01 \times(0.9801)}{0.01 \times (0.9801)+ 0.99(4 \times 10^{-4})}[/tex]

the probability that he is a drug user since  failed his second drug test

= [tex]\dfrac{0.009801}{0.009801+ 3.96 \times 10^{-4}}[/tex]

the probability that he is a drug user since  failed his second drug test

= 0.961165


Related Questions

Joey’s pizza sells large cheese pizzas for $12.00. Each additional topping costs $0.50. Basketball Boosters bought 12 large pizzas, each with 3 toppings. There are 8 slices per pizza. How much does it cost per slice? Round to the nearest cent.

Answers

Answer:

So first you do $0.50 x 3 = 1.5

then you add that to $12.00

$12.00 + 1.5 = 13.5

13.5 is the cost of one pizza.

Since they bought 12:

The total cost of the 12 pizza is $162 <== not important

13.5 divided by 8 is 1.687

round 1.56875 to the nearest cent 1.7 = $2

so each slice costs $2

Use the frequency distribution, which shows the number of American voters (in millions) according to age, to

find the probability that a voter chosen at random is in the 18 to 20 years old age range

Ages

18 to 20

21 to 24

25 to 34

35 to 44

45 to 64

65 and over

Frequency

4.2

7.8

20.8

23.7

50.1

28 2

Date

07/2

3:29

The probability that a voter chosen at random is in the 18 to 20 years old age range is 0.0311

(Round to three decimal places as needed.)

07/2

8:52

Question Viewer

07/1

8:03

07/1

5:46

>

07/1

12:2

07/1

5:39

07/1

2:42

Question is complete. Tap on the red indicators to see incorrect answers.

07/1

12:00

Answers

Answer:

The probability that a voter chosen at random is in the 18 to 20 years old age range is =  4.2/ 134.8= 0.0311572

Step-by-step explanation:

We can find the probability by simply dividing the frequency of the ages range of 18-20 by the total frequency.

Ages                Frequency

18 to 20             4.2

21 to 24             7.8

25 to 34           20.8

35 to 44           23.7

45 to 64           50.1

65 and over       28.2

∑                        134.8

The probability of an event is given by the occurrence of an event by the total occurrences .

So

Here the occurrence of ages 18-20 is given by 4.2

and the total frequency is 134.8

The probability that a voter chosen at random is in the 18 to 20 years old age range is =  4.2/ 134.8= 0.0311572

A certain game involves tossing 3 fair coins, and it pays .14 for 3 heads, .06 for 2 heads, and .01 for 1 head. The expected winnings are?

Answers

Answer:

Total expected amount = $0.04375

Step-by-step explanation:

We need to calculate probability of getting heads on every combination of coin tosses

HHH = 1/8 = 3 heads

HHT = 1/8 = 2 heads

HTH = 1/8 = 2 heads

HTT = 1/8 = 1 head

THH = 1/8 = 2 heads

THT = 1/8 = 1 head

TTH = 1/8 = 1 head

TTT = 1/8 = 0 head

So the probability of 3 heads is 1/8 and the amount is (1/8)* 0.14 = $0.0175

Probability of 2 heads is 3/8 and the amount is (3/8) * 0.06 = $0.0225

Probability of 1 head is 3/8 and amount is (3/8) * 0.01 = $0.00375

Total expected amount = 0.00375 + 0.0225 + 0.0175

Total expected amount = $0.04375

If the weight (in grams) of cereal in a box of Lucky Charms is N(470,5), what is the probability that the box will contain less than the advertised weight of 453 g?

Answers

Answer:

The probability that the box will contain less than the advertised weight of 453 g is 0.00034.

Step-by-step explanation:

Let X represent the weight (in grams) of cereal in a box of Lucky Charms.

It is provided that X follows a Normal distribution with parameters, μ = 470 and σ = 5.

Compute the probability that the box will contain less than the advertised weight of 453 g as follows:

[tex]P(X<453)=P(\frac{X-\mu}{\sigma}<\frac{453-470}{5})[/tex]

                  [tex]=P(Z<-3.4)\\=0.00034[/tex]

*Use the z-table.

Thus, the probability that the box will contain less than the advertised weight of 453 g is 0.00034.

The following is the number of minutes to commute from home to work for a group of 25 automobile executives. 35 36 39 43 37 35 34 30 36 34 30 39 37 40 38 33 31 28 39 35 35 36 41 24 36 How many classes would you recommend? What class interval would you suggest? (Round up your answer to the next whole number.) Organize the data and plot a frequency distribution on a piece of paper. Comment on the shape of the frequency distribution. It is not symmetric. It is fairly symmetric, with most of the values between 24 and 43. It is not very symmetric, but most of the values lie between 24 and 43.

Answers

Answer:

It is not symmetric, but skewed left. Data appears more to be on the left side.

Step-by-step explanation:

The smallest value is 24 and the largest is 43 . The difference between these two values is 19 which can be divided into into intervals of 4.

19/4= 4.75 It will be rounded to 5.

The class interval can of 5. Starting from 20 we get class intervals and frequency distribution as

Class Intervals          Data                                        Frequency      

20-24                           24                                              1

25- 29                           28,                                            1

30-34                            34,30,34,30,33,31,                   6

35-39                         35,36,39,37,35,36,39,37,           14

                                         38,39,35,35,36,36

40-44                                43,40,41                                3

The class intervals are inclusive of both upper and lower limits. The difference between the lower limits of two consecutive classes or upper limits of two consecutive classes must be the same.

As we see the difference here is that of 5 between the two upper or lower limits of consecutive classes.

The histogram is attached which shows the class intervals along x- axis and data frequency along y- axis.

Can I have somebody answer a few more of the questions that I need please and this one too?

Answers

Answer:

x > 22

Step-by-step explanation:

Hey there!

Well to solve,

52 - 3x < -14

we need to single out  x

52 - 3x < -14

-52 to both sides

-3x < -66

Divide both sides by -3

x > 22

The < changes to > because the variable number is a - being divided.

Hope this helps :)

Answer:

x > 22

Step-by-step explanation:

First, rearrange the equation

52 - 3 × x - (-14) < 0

Then, pull out the like terms:

66 - 3x

Next, apply algebra to the equation by dividing each side by -3. It should now look like this: x > 22.

Therefore, the solution set of the inequality would be x > 22.

A publishing company claims that in fall 2019, the average price of college textbooks for a single semester is $385. Suppose you decide to collect data from a random sample of students to assess whether the publisher's claim is reasonable, and you find that in a random sample of 22 college students, the mean price of textbooks for the fall 2019 semester was $433.50 with a standard deviation of $86.92. At the 0.01 significance level, is there sufficient evidence to conclude that the mean price of college textbooks for a single semester is different from the value claimed by the publisher?

Answers

Answer:

We accept H₀ . We don´t have enough evidence to express the publisher claim is not true

Step by Step explanation:

We must evaluate if the mean of the price of college textbooks is different from the value claimed by the publisher

n < 30 then we must use t - distrbution

degree of freedom   n  - 1     df = 22 - 1     df = 21

As the question mentions " different " that means,  a two-tail test

At 0,01 significance level     α  = 0,01       α/2  =  0,005

and t(c)  = 2,831

Test Hypothesis

Null Hypothesis                      H₀          μ  =  μ₀

Alternative hypothesis           Hₐ          μ  ≠  μ₀

To calculate t(s)

t(s)  =  (  μ  -  μ₀ ) /σ/√n

t(s)  =  (  433,50 - 385 ) / 86,92 / √22

t(s)  =  2,6171

Comparing   t(c)   and t(s)

t(s) < t(c)

Then  t(s) is in the acceptance region we accept H₀. We don´t have enough evidence to claim that mean price differs from publisher claim

How long will it take $3800 to grow into $5700 if it’s invested at 6% interest compounded continuously?

Answers

Answer: 25 years

Step-by-step explanation:

t = I / Pr

t = 5700 / ( 3800 × 0.06 ) = 25

t = 25 years

PLEASE HELP QUICK!!!!!!! Find the length of a rectangle that has one side of length 8 and area 32

Answers

Answer:

4

Step-by-step explanation:

Length of one side=8

Area=32

Length of another side=x

8 into x = 32

X=32/8

=4

Ava placed the point of her pencil on the origin of a regular coordinate plane. She marked a point after moving her pencil 4 units to the left and 7 units up. Which ordered pair identifies where Ava marked her point?

Answers

[tex] \Large{ \boxed{ \bold{ \color{lightgreen}{Solution:}}}}[/tex]

So, Let's solve this question by using cartesian plane.

Here, Origin is shown by (0, 0)Ava moves 4 units left from origin. On the left side of origin, negative x axis begins. So, she reached (-4, 0) now.Then, from that point she moved 7 units upwards. On the upper side, there is positive y axis. So, Finally she will reach point (-4, 7).(-4, 7) is the coordinate of point which is 4 units left from y axis and 7 units up from x axis.It lies on the second quadrant.

Well, What is cartesian plane?

A - A Cartesian coordinate system is a coordinate system that specifies each point uniquely in a plane by a set of numerical coordinates, which are the signed distances to the point from two fixed perpendicular oriented lines, measured in the same unit of length. 

━━━━━━━━━━━━━━━━━━━━

The sum of 8 times a number and 7 equals 9!

Answers

Answer:

0.25*8+7=9

Step-by-step explanation:

8x+7=9

2/8=x

0.25=x


Which of the following is the correct notation of the complex number?

Answers

Answer:

-84 + 10i

Step-by-step explanation:

Standard Complex Form: a + bi

Step 1: Evaluate

√-100 = √-1 x √100 = i x 10 = 10i

-84 = -84

Step 2: Combine

10i - 84

Step 3: Rearrange

-84 + 10i

Answer:

Last Option

Step-by-step explanation:

√-100 - 84

(√(100×-1)) - 84

(√100)(√-1)-84

√-1 = i

10i - 84 or -84 + 10i

If the nth term is , then the (n+1)st is: Please make sure you check the image :)

Answers

Answer:

( n+1) /2 *( 3n+2)

Step-by-step explanation:

n/2 * ( 3n-1)

We want the n+1 term

Replace n with n+1

( n+1) /2 *( 3( n+1) -1)

Distribute

( n+1) /2 *( 3n+3 -1)

( n+1) /2 *( 3n+2)

Answer:

[tex]\large \boxed{\sf C. \ \frac{n+1}{2} (3n+2)}[/tex]

Step-by-step explanation:

[tex]\displaystyle \frac{n}{2} (3n-1)[/tex]

To find the (n+1)st term, replace the n variable with n+1.

[tex]\displaystyle \frac{n+1}{2} (3(n+1)-1)[/tex]

Expand brackets.

[tex]\displaystyle \frac{n+1}{2} (3n+3-1)[/tex]

Subtract like terms in brackets.

[tex]\displaystyle \frac{n+1}{2} (3n+2)[/tex]

2. Write the equation of the circle in general form. Show your work.

Answers

Answer:

[tex] {(x + 1)}^{2} + {(y - 1)}^{2} = 9[/tex]

[tex] {x} ^{2} + {y} ^{2} + 2x - 2y - 7 = 0 [/tex]

HELP PLZ A circle inscribed in a triangle:

Answers

Answer:

The answer is the second photo.

Step-by-step explanation:

It's literally a circle in a triangle. So, it's the second one.

Rational equation of 3/x+1=2/x-3

Answers

Answer:

x = 11

Step-by-step explanation:

3/x+1=2/x-3

Solve by using cross products

2 (x+1) = 3 (x-3)

Distribute

2x+2 = 3x-9

Subtract 2x

2x+2-2x = 3x-2x-9

2 = x-9

Add 9 to each side

2+9 =x-9+9

11 =c

the bold answer is incorrect. what is the right answer?

Answers

Answer: first choice

Explanation:

A complementary angle are two angles add up to 90 degree

Use the dot product to determine whether v and w are orthogonal.

v=-i-j, w=-i+j

Select the correct choice below and fill in the answer box to complete your choice.

O A. The vectors v and w are not orthogonal because their dot product is ___

O B. The vectors v and w are orthogonal because their dot product is ___

Answers

Answer:

B. The vectors v and w are orthogonal because their dot product is 0

Step-by-step explanation:

Given that :

v=  - i - j  

w= - i + j

Therefore;

vw = ( - i - j )  ( - i + j )

Taking each  set of integer of the vector into consideration:

vw = ( -1 × - 1) ( -1 × 1)

vw = 1 - 1

vw = 0

Hence, we can conclude that :

The vectors v and w are orthogonal because their dot product is 0  

I need help ? which linear function is represented by the graph?​

Answers

Answer: f(x) = (-1/2)x+1, choice B

=================================================

Explanation:

The diagonal line passes through 1 on the vertical y axis. So the y intercept is b = 1. This means the location of the y intercept is (0,1).

Start at (0,1) and move down 1 and to the right 2 to arrive at (2,0). This is another point on the diagonal line. The motion of "down 1 and right 2" is effectively the slope

slope = rise/run = -1/2

rise = -1, run = 2

The rise being negative means we have gone downhill as we move to the right.

With m = -1/2 as the slope and b = 1 as the y intercept, we go from y = mx+b to y = (-1/2)x+1

The last thing to do is replace y with f(x) to get f(x) = (-1/2)x+1 as the final answer.

Answer:

it's b

Step-by-step explanation:

b

What is the 25th term in the following arithmetic sequence? -7, -2, 3, 8, ...

Answers

Answer:

108.

Step-by-step explanation:

-7, -2, 3, 8 is an arithmetic sequence with a1 (first term) = -7 and common difference (d)  = 5.

The 24th term = a1 + (24 - 1)d

=  -7 + 23 * 5

= -7 + 115

= 108.

Identify the recursive formula for the sequence given by the explicit formula f(n) = 20 – 4(n − 1).

Answers

Answer:

[tex]\huge\boxed{f(n)=\left\{\begin{array}{ccc}f(1)=20\\f(n)=f(n-1)-4\end{array}\right}[/tex]

Step-by-step explanation:

[tex]f(n)=20-4(n-1)=20+(n-1)(-4)\\\\\text{It's an explicit formula of an arithmetic sequence:}\\\\f(n)=a_1+(n-1)(d)\\\\a_1-\text{first term}\\d-\text{common difference}\\\\\text{Conclusion:}\\\text{Next term}=\text{previous one}\ -4\\\\\text{The recursive formula:}\\\\\huge\boxed{f(n)=\left\{\begin{array}{ccc}f(1)=20\\f(n)=f(n-1)-4\end{array}\right}[/tex]

Answer:

Step-by-step explanation:

someone answered already

Enclosing the Largest Area The owner of the Rancho Grande has 3,052 yd of fencing with which to enclose a rectangular piece of grazing land situated along the straight portion of a river. If fencing is not required along the river, what are the dimensions (in yd) of the largest area he can enclose

Answers

Answer:

the shorter side = 1526

the longer side = 763

area = 1164338

Step-by-step explanation:

lets say

a=length

b = width

a + 2b = 3052

this is the perimeter

such that

a = 3052 - 2b

the area of a rectangle is a*b

= (3052 - 2b)b

= 3052b - 2b²

we differentiate this to get:

= 3052 - 4b

such that

3052 = 4b

divide through by 4, to get b, the width

3052/4 = 763

b = 763

put the value of b into a

a = 3052 - 2b

a = 3052 - 2(763)

a = 3052 - 1526

a = 1526

therefore

the shorter side = 1526

the longer side = 763

area = a x b

area = 1526 x 763

area = 1526 x 763

= 1164338

the grasshopper population in Georgia is currently 4,000. It's growing by 2.3% each year. Write an equation that models the situation.

Answers

Answer:

[tex]4000(1.023)^t\\\\[/tex]

Step-by-step explanation:

Using this exponential growth equation we can get an equation that models the situation.

A= Principal Amount

R= Rate of Growth

T= Amount of time

[tex]A=4000\\R=2.3/100=.023\\T= Non[/tex]

[tex]A(1+R)^t\\4000(1+0.23)^t\\4000(1.023)^t\\\\[/tex]

If there are 80 students in a class and 20 are seniors, what proportion of students are not seniors?

Answers

Answer:

3/4

Step-by-step explanation:

First find the number that are not seniors

80 -20 = 60

60 are not seniors

The ratio of not seniors to total

60/80

Divide top and bottom by 20

3/4

Answer:

60 students

Step-by-step explanation:

80 -20 = 60

What is the volume of a square pyramid whose length of one side of its base is 9cm and whose height is 15cm. Show your work

Answers

Answer:

The answer is 405cm³

Step-by-step explanation:

Volume of a pyramid is given by

[tex]V = \frac{1}{3} \times area \: of \: base \: \: \times height[/tex]

height = 15cm

From the question the pyramid is a square pyramid which means it's base is a square

Area of a square = l²

where l is the length of one side

l = 9cm

Area of square = 9² = 81cm²

So the volume of the pyramid is

[tex]V = \frac{1}{3} \times 81 \times 15[/tex]

[tex]V = 27 \times 15[/tex]

We have the final answer as

V = 405 cm³

Therefore the volume of the pyramid is

405cm³

Hope this helps you

a company should stop making a part internally and buy externally when

Answers

Answer:

Make-or-Buy Decision

Step-by-step explanation:

Which phrase describes the algebraic expression 8f+7?
the product of 8 and 7 more than a number
the quotient of 8 and 7
8 times the sum of a number and 7
8 times a number plus 7​

Answers

Answer:

8 times a number plus 7

Step-by-step explanation:

Let the number be f.

Simply, 8 f+7 is the expression.

Thank you!

Billy has x marbles. Write an expression for the number of marbles the following have… a) Charlie has 5 more than Billy b) Danny has 8 fewer than Billy c) Eric has three times as many as Billy

Answers

Answer:

Charlie: 5 + xDanny: x - 8Eric: x × 3

If the sum of the daily unpaid balances is $7,812 over a 31-day billing cycle, what is the average daily balance?

Answers

Answer:

252

Step-by-step explanation:

Divide 7812 by 31 and we get the average daily answer... Hope this helps!!

What is the equation of the parabola that has its vertex at (8,-1) and a y-intercept of (0,-17)?

Answers

y = a(x  + 1.5)^2 - 12.5

y intercept is (0,-8) so:-

-8 = a(0+1.5)^2 - 12.5

-8 = 2.25a - 12.5

a =  4.5/ 2.25 = 2

so we have  

y  = 2 ( x +1.5)^2 - 12.5

solving for x  when y = 0:-

(x + 1.5)^2 = 12.5/2 = 6.25

taking sqrt's  x + 1.5  = +/- 2.5

x =  -4,   1

so the x intercepts are (-4,0) and (1,0)

Answer:

y = –1∕4(x – 8)^2 – 1

Step-by-step explanation:

I took the exam and  got  it  right.

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