Random samples of size 81 are taken from a population whose mean is 45 and standard deviation is 9. Calculate the probability that a sample mean is less than 42. (round to 4 decimal places)
HINT: When you randomly select a group (n > 1) then you need to re-calculate the standard deviation using the formula:
σ n

Answers

Answer 1

Answer:

Using z table

                         = 0.0013

The probability = 0.0013

Step-by-step explanation:

Given that,

mean = μ = 45

standard deviation = σ   = 9

n=81

μT = μ =45

[tex]\sigma T = \sigma / \sqrt n = 9 / \sqrt81 =1[/tex]

[tex]P(T <42 )\\= P[(T - \mu T ) / \sigma T < (42-45) /1 ]\\\\= P(z <-3 )[/tex]

Using z table

= 0.0013

probability= 0.0013


Related Questions

show that the line x-y+2=0 and the line joining the points (4,6) and (10,12) are parallel to each other

Answers

x-y+2=0

-y= -x-2

y=x+2

In order for the other line to be parallel, the slope has to be the same.

(12-6)/(10-4)= 6/6= 1

Both slopes are the same, meaning it is parallel.

Show that the equation 2x + 3 cos x + e ^ x = 0 has a root on the interval [- 1, 0]

Answers

If x = -1, you have

2(-1) + 3 cos(-1) + e ⁻¹ ≈ -0.0112136 < 0

and if x = 0, you have

2(0) + 3 cos(0) + e ⁰ = 4 > 0

The function f(x) = 2x + 3 cos(x) + is continuous over the real numbers, so the intermediate value theorem applies, and it says that there is some -1 < c < 0 such that f(c) = 0.

Given the directrix of y = 4 and focus of (0, 2), which is the equation of the parabola?

Answers

Answer:

The equation of the parabola is,

x²+4y-12=0

how many wall are there in your room? what are the shape of the floor and ceiling in your room ? how can you find the area of each shape?prepare the answer. present the conclusion in the form of report. plz answer the question in right.​how many wall are there in your room? what are the shape of the floor and ceiling in your room ? how can you find the area of each shape?prepare the answer. present the conclusion in the form of report. plz answer the question in right. plz answer the question steps by step.​

Answers

Answer:

4 walls in my room. The shape of my room is square and my ceiling in square. By looking at it and measuring it. Thats how I found my answer.

I believe this is correct if it is can you mark brainliest? Hope I helped!!!! :)

Answer:

8 walls etc....

Step-by-step explanation:

You can work a total of no more than 35 hours each week at your two jobs. Housecleaning pays $7 per hour and your sales job pays $9 per hour. You need to earn at least $314 each week to pay your bills. Write a system of inequalities that shows the various numbers of hours you can work at each job.​

Answers

Answer: 7x + 9y >_ (more or equal) 314

X + Y <_ ( less or equal) 35

Step-by-step explanation:

Answer:

h+s≤35 and 7h + 9s >_314

Step-by-step explanation:

Put the following equation of a line into slope-intercept form, simplifying all
fractions.
18x + 3y = -18

Answers

Answer:

y= -6x-6, I think, hope it helped

Step-by-step explanation:

Do the two trapezoids in the figure appear to be similar? Why or why not?
options:

A)

They're not similar because only one pair of corresponding angles in the two trapezoids is congruent.

B)

They're similar because two pairs of corresponding angles in the two trapezoids are congruent.

C)

They're similar because one pair of corresponding angles in the two trapezoids is congruent.

D)

They're not similar because two pairs of corresponding angles in the two trapezoids are congruent.

Answers

Answer:

Option B,

They're similar because two pairs of corresponding angles in the two trapezoids are congruent

Answer:

They're not similar because only one pair of corresponding angles in the two trapezoids is congruent.

Step-by-step explanation:

Reflect the given triangle over
the y-axis.
[3 6 3 ]
[-3 3 3]

Answers

Answer:

Step-by-step explanation:

[tex]\left[\begin{array}{ccc}x_{1} &x_{2} &x_{3} \\y_{1} &y_{2} &y_{3} \end{array}\right][/tex]  ---------> [tex]\left[\begin{array}{ccc}-x_{1} &-x_{2} &-x_{3} \\y_{1} &y_{2} &y_{3} \end{array}\right][/tex]

[tex]\left[\begin{array}{ccc}-3&-6&-3\\-3&3&3\end{array}\right][/tex]

Tay-Sachs disease is a genetic disorder that is usually fatal in young children. If both parents are carriers of the disease, the probability that their offspring will develop the disease is approximately 0.25. Suppose that a husband and wife are both carriers and that they have four children. If the outcomes of the four pregnancies are mutually independent, what are the probabilities of the following events?
a. All three children will develop Tay–Sachs disease.
b. Only one child will develop Tay–Sachs disease.
c. The third child will develop Tay–Sachs disease, given that the first two did not.

Answers

Lo siento mucho, necesito los puntos porque estoy en una prueba.

If a right circular cone has radius 4 cm and slant height 5cm then what is its volume?​

Answers

Answer:

V≈50.27cm³

Step-by-step explanation:

Using the formulas

V=πr2h

3

l=r2+h2

Solving forV

V=1

3πr2l2﹣r2=1

3·π·42·52﹣42≈50.26548cm³

Which graph best represents the equation 5x + 2y = 7?

Answers

Answer:

D

Does the answer help you?

Answer:

D

Step-by-step explanation:

A rectangle has an area of 616 m² and a width of 22m. What is its length?

Answers

Answer:

l=28m

w Width

22

m

A Area

616

Using the formula

A=wl

Solving forl

l=A

w=616

22=28m

hope this will help you

make me brainliest

Answer:

Solve for length

l=28m

W= Width

22

m

A= Area

616

Using the formula

A=wl

Solving formula

l=A

W=616

22=28m

PLSSS HELP IM STRUGGLING SO HARD !!! ———————

Answers

Answer:

C)

Step-by-step explanation:

Just see the length of the R line, A and B are almost the same large when you add them.

Answer:

C).

Step-by-step explanation:

Because it is the largest side in that specific triangle

What is log10^6, considering log10^2=a and log10^3=b?

Answers

The answer is simply just a+b.

Solution:

log10^6=log10^2+log10^3

Since log10^2=a and log10^3=b,

The answer is a+b.

I think that the answer is a+b.

Which of the following sets are equal to {x|x < 9 and x> 2}

{3,4,5,6,7,8}

{2,3,4,5,6,7,8,9}

{}

{2,3,4,5,6,7}

Answers

Answer:

{3, 4, 5, 6, 7, 8}

Step-by-step explanation:

{x|x < 9 and x > 2}= {3, 4, 5, 6, 7, 8}

[tex]\tt{ \green{P} \orange{s} \red{y} \blue{x} \pink{c} \purple{h} \green{i} e}[/tex]

estimate the value of -50 by plotting it on a number line
[tex] - \sqrt{50} [/tex]
how to plot -50 on a number line​

Answers

Answer:

Step-by-step explanation:

Never mind the minus for a second. What is the approximate value of sqrt(50)?

Isn't it about 7 or just a tiny bit over?

That's the answer here. Find the square root first, and then add the minus.

<o==o==o==o==o==o==o==o

  -7  -6  -5  -4  - 3  - 2  - 1    0

9.) Ezri earns $10 per day plus $25 for every lawn she mows. How many lawns does she need to mow today to earn $135? First, write the equation that fits this model. Let x be the amount of yards she mows. Hurry please

Answers

Answer:

5 lawns

Step-by-step explanation:

Firstly, the equation is 25x + 10 = 135

Ezri makes $25 for every lawn she mows (25x) and has an automatic $10 per day (10). In order to make $135 we take what she makes each day and set it equal to 135.

To solve, we subtract 10 from both sides to create 25x = 125. We then divide 25 from both sides to get x=5. This means that Ezri needs to mow 5 lawns in order to make $135.

I hope this is helpful to you!

**To anyone out there seeing this - let me know if you think I made a mistake and I will fix it.**

a Merchant of New York bought some goods from Nepal worth Rs 55680 if 1 dollar = rs 72.50 and £1= Rs 128 if by sending money through London he saves 19.80 Dollars find the rate of exchange between new York and London? ​

Answers

Answer:

$1.85 = £1

Step-by-step explanation:

55680/72.50 = 786

55680/128 = 435

435x = (786 + 19.80)

x = 805.8/435

x = 1.85

Answer:

£1 = $1.72

Step-by-step explanation:

55680/72.50=768

55680/128=435

768.00 - 19.80 = 748.20

x = 748.20 / 435

x = $1.72

The graph shows the distribution of the number of text messages young adults send per day. The distribution is approximately Normal, with a mean of 128 messages and a standard deviation of 30 messages.

A graph titled daily text messaging has number of text on the x-axis, going from 8 to 248 in increments of 30. Data is distributed normally. The highest point of the curve is at 128.

What percentage of young adults send between 68 and 158 text messages per day?

34%
47.5%
81.5%
95%

Answers

Answer:  C) 81.5%

This value is approximate.

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

Explanation:

We have a normal distribution with these parameters

mu = 128 = population meansigma = 30 = population standard deviation

The goal is to find the area under the curve from x = 68 to x = 158, where x is the number of text messages sent per day. So effectively, we want to find P(68 < x < 158).

Let's convert the score x = 68 to its corresponding z score

z = (x-mu)/sigma

z = (68-128)/30

z = -60/30

z = -2

This tells us that the score x = 68 is exactly two standard deviations below the mean mu = 128.

Repeat for x = 158

z = (x-mu)/sigma

z = (158-128)/30

z = 30/30

z = 1

This value is exactly one standard deviation above the mean

-------------------------------------------

The problem of finding P(68 < x < 158) can be rephrased into P(-2 < z < 1)

We do this because we can then use the Empirical rule as shown in the diagram below.

We'll focus on the regions between z = -2 and z = 1. This consists of the blue 13.5% on the left, and the two pink 34% portions. So we will say 13.5% + 34% + 34% = 81.5%

Approximately 81.5% of the the population sends between 68 and 158 text messages per day. This value is approximate because the percentages listed in the Empirical rule below are approximate.

Answer:

C. 81.5%

Step-by-step explanation:

What is the greatest common factor of 10 and 13?
ANSWER IN LESS THEN 3 MINS AND I'LL GIVE BRAINLIEST

Answers

Answer:

the answer for this would be 1

Tenisha solved the equation below by graphing a system of equations.
log35x = log (2x+8)
Which point approximates the solution for Tenisha's system of equations?
0 (0.9, 0.8)
O (1.0, 1.4)
O (2.3, 1.1)
O (2.7, 13.3)

Answers

Answer:

Option B.)

Step-by-step explanation:

Just took the test and got 100% :]

The system of logarithmic equation is graphed and the point of intersection of the equation is log₃ ( 5x ) = log₅ ( 2x + 8 ) is A ( 1.0 , 1.4 )

What is Equation of Graph of Polynomials?

Graphs behave differently at various x-intercepts. Sometimes the graph will cross over the x-axis at an intercept. Other times the graph will touch the x-axis and bounce off.

Identify the even and odd multiplicities of the polynomial functions' zeros.

Using end behavior, turning points, intercepts, and the Intermediate Value Theorem, plot the graph of a polynomial function.

The graphs cross or are tangent to the x-axis at these x-values for zeros with even multiplicities. The graphs cross or intersect the x-axis at these x-values for zeros with odd multiplicities

Given data ,

Let the solution to the logarithmic equation be represented as A

Now , the value of A is

log₃ ( 5x ) = log₅ ( 2x + 8 )

On simplifying , we get

log₃ ( 5x ) = log₁₀ ( 5x ) / log₁₀ ( 3 )

log₅ ( 2x + 8 ) = log₁₀ ( 2x + 8 ) / log₁₀ ( 5 )

Substituting the logarithmic quantities , we get

log₁₀ ( 5x ) / log₁₀ ( 3 ) = log₁₀ ( 2x + 8 ) / log₁₀ ( 5 )

On cross multiplying , we get

log₁₀ ( 5x ) / log₁₀ ( 2x + 8 ) = log₁₀ ( 3 ) / log₁₀ ( 5 )

( 5x ) / ( 2x + 8 ) = 3/5

On cross multiplying , we get

25x = 6x + 24

Subtracting 6x on both sides , we get

19x = 24

Divide by 19 on both sides , we get

x = 1.26

Therefore , the approximate values of the function on graphing is A ( 1.0 , 1.4 )

Hence , the solution of function from graphing is A ( 1.0 , 1.4 )

To learn more about equation of graph of polynomials click :

https://brainly.com/question/16957172

#SPJ7

HELP ME PLSSS SUMMER SCHOOL A HARD

Answers

Answer:

y=2x+8

Step-by-step explanation:

Hope this helps

A manufacturer of potato chips would like to know whether its bag filling machine works correctly at the 409 gram setting. It is believed that the machine is underfilling the bags. A 21 bag sample had a mean of 401 grams with a standard deviation of 26. A level of significance of 0.1 will be used. Assume the population distribution is approximately normal. Determine the decision rule for rejecting the null hypothesis. Round your answer to three decimal places.

Answers

Answer:

The decision rule is to Reject H0 if Z ≤ -1.282

Step-by-step explanation:

We are given;

Population mean; μ = 409 g

Sample mean; x¯ = 401 g

Sample size; n = 21

Standard deviation; s = 26

Let's define the hypotheses;

Null hypothesis; H0: μ = 409 g

Alternative hypothesis; Ha : μ ≠ 409 g

Formula for test statistic is;

z = (x¯ - μ)/(s/√n)

z = (401 - 409)/(26/√21)

z = -1.410

z-value is negative and thus this is a lower tail test.

At significance level of 0.1, the critical value is -1.282.

Thus, the decision rule is;

Reject H0 if Z ≤ -1.282

Integers are sometimes whole numbers

true or false

Answers

Answer:

True

Step-by-step explanation:

Integers are always whole numbers

negative, 0, positive:: whole numbers

. Two mutually exclusive projects have projected cash flows as follows:
YEAR PROJECT A PROJECT B
0 Ksh. -2m Ksh. -2m
1 1m 0
2 1m 0
3 1m 0
4 1m 6m





Required:
a) Determine the internal rate of return for each project. [2 Marks]

b) Determine the net present value for each project at discount rates of 0, 5,10,20,30, and 35 percent. [2 Marks]

c) Plot a graph of the net present value of each project at the different discount rates. [2 Marks]

d) Which project would you choose? Why? [ 2 Marks]

e) What is each project’s MIRR if the cost of capital is 12 percent?

Answers

Answer:

yes

Step-by-step explanation:

Help me please guys thanks

Answers

Answer:

A is correct

Step-by-step explanation:

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

Can you help with this

Answers

9514 1404 393

Answer:

  D, C

Step-by-step explanation:

The only two rational expressions that have appropriate denominators are ...

  1/(x² +6x) . . . contributes a factor of x to the denominator

  (x+2)/(x² -36) . . . contributes a factor of (x -6) to the denominator

The proper order in the expression is ...

  [tex]\displaystyle\dfrac{x+2}{x^2-36}-\dfrac{1}{x^2+6x}=\dfrac{x^2+x+6}{x(x-6)(x+6)}[/tex]

Answer:

(x+2/x^2-36) - (1/x^2+6x) = (x^2+x+6/x(x-6)(x+6))

Step-by-step explanation:

I hope that helps

As a student, you are able to earn extra money by assisting your neighbors with odd jobs.
If you charged $10.25 an hour for your assistance, about how many hours would you
need to work to earn $8,425? Show your work. (

Answers

9514 1404 393

Answer:

  about 822 hours

Step-by-step explanation:

If h is the number of hours for which you are paid $10.25 per hour, then the number you need is ...

  8425 = 10.25h

Divide by the coefficient of h:

  8425/10.25 = 10.25h/10.25

  821.95121...(5-digit repeating decimal)

You need to work about 822 hours to earn $8425.

_____

Your pay for 822 hours will be $8425.50. If taxes are deducted, you need to work a while longer.

Use the Unit Circle to find the exact value of the trig function. Cos(45)

1/2
√2/2
√3/-2
1

Answers

In a unit circle a line reaching from origin to the circle's circumference specifies the trigonometric functions.

A point where the line which comes from origin to the circumference intersecting it has coordinates [tex](\cos\theta,\sin\theta)[/tex].

In our case [tex]\theta=45^\circ[/tex] which lifts the line up by 45 degrees and makes it intersect circumference at [tex](\cos45^\circ,\sin45^\circ)[/tex].

In the upper right quadrant the angle between x and y axis is 90 degrees so a line coming in at angle of 45 degrees would split the quadrant in half, that means sine and cosine 45 degrees will be equal.

As you may noticed a point has coordinates cos, sin which means the distance between 0 and y coordinate where the point on a circle is, is called [tex]\cos\theta=\cos45^\circ[/tex].

Because cosine 45 degrees is so simple in interpretation it has a known value of [tex]\cos45^\circ=\sin45^\circ=\frac{\sqrt{2}}{2}[/tex].

Hope this helps :)

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