help me with this question!

Answer:

The t-distribution is used, as we have the standard deviation of the sample.

The 95% confidence interval for the population mean time wasted is between 7.12 hours and 8.88 hours.

Step-by-step explanation:

We have the standard deviation for the sample, which meas that the t-distribution should be used to solve this question.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 81 - 1 = 80

95% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 80 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.95}{2} = 0.975[/tex]. So we have T = 1.99

The margin of error is:

[tex]M = T\frac{s}{\sqrt{n}} = 1.99\frac{4}{\sqrt{81}} = 0.88[/tex]

In which s is the standard deviation of the sample and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 8 - 0.88 = 7.12 hours.

The upper end of the interval is the sample mean added to M. So it is 8 + 0.88 = 8.88 hours.

The 95% confidence interval for the population mean time wasted is between 7.12 hours and 8.88 hours.

Answer:

47.12389 Rounded is 47.12

Step-by-step explanation:

V=πr2h=π·12·15≈47.12389

Answer: A

Step-by-step explanation: -20

Answer:

Approximately 68% of the students have grade point averages that are between 2.13 and 2.99.

Step-by-step explanation:

The Empirical Rule states that, for a normally distributed random variable:

Approximately 68% of the measures are within 1 standard deviation of the mean.

Approximately 95% of the measures are within 2 standard deviations of the mean.

Approximately 99.7% of the measures are within 3 standard deviations of the mean.

In this question, we have that:

Mean = 2.56

Standard deviation = 0.43

What percentage of the students have grade point averages that are between 2.13 and 2.99?

2.56 - 0.43 = 2.13

2.56 + 0.43 = 2.99

Within one standard deviation of the mean, so, by the Empirical Rule:

Approximately 68% of the students have grade point averages that are between 2.13 and 2.99.

Answer: 7

Step-by-step explanation:

2x - 3 = x + 4

2x - x - 3 = 4           Mius x from the both side

       x - 3 = 4          

             x = 7          Add the 3 from both side

Answer:

follow me and followback kita

Step-by-step explanation:

legit hindi ko alam sagot

9514 1404 393

Answer:

  12 m³

Step-by-step explanation:

The bottom platform has dimensions 2m × 4m × 3m, so a volume of ...

  V = LWH

  V = (2 m)(4 m)(3 m) = 24 m³

The top platform has dimensions 2m × 3m × 2m, so a volume of ...

  V = (2 m)(3 m)(2 m) = 12 m³

The bottom platform has a larger volume by ...

  24 m³ -12 m³ = 12 m³

The bottom prism has a 12 m³ larger volume.

Answer:

the answer is 12m squared

Answer:

c. Cos 52 = 17/c

Step-by-step explanation:

sin(x) = cos(90-x)

Step-by-step explanation: When finding the coordinates

of a given point, be very careful with your signs.

On the x-axis, left means negative and right means positive and

on the y-axis, down means negative, and up means positive.

So to find the coordinates for point A, we start at the origin,

which is the point (0, 0), and we move 2 units to the left and 4 units up.

So that's the point (-2, 4).

Remember to go left or right first, then up or down.

So for point B, we go 0 units to the left or right and 3 units down.

So that's the point (0, -3).

For point C, we move 4 units to th

right and 4 units down so tha's (4, -4).

Answer:

x=amount invested at 7%

2x=amount invested at 8%

3x=amount invested at 9%

interest=principal*rate*time (time=1 year)

$150=0.07x+0.08*2x+0.09*3x

$150=0.07x+0.16x+0.27x

$150=0.50x

$1500=5x

x=$300 invested at 7%

2x=$600 invested at 8%

3x=$900 invested at 9%

Step-by-step explanation:

Answer:

i think the answer is 10.5

Step-by-step explanation:

1.25 for a gallon means that 1.25 x 8 = 10. 0.4 gallons mean 1.25 divided by 0.4 which gets you 0.5. I think that's the right answer

Hope this helps!

Mark brainliest please

Answer:

$10.50

Step-by-step explanation:

Answer:

B

Step-by-step explanation:

i got it right

Answer:

Step-by-step explanation:

If two pairs of corresponding angles in a pair of triangles are congruent, then the triangles are similar. We know this because if two angle pairs are the same, then the third pair must also be equal. When the three angle pairs are all equal, the three pairs of sides must also be in proportion.

Two triangles are said to be similar if their corresponding angles are congruent and the corresponding sides are in proportion . In other words, similar triangles are the same shape, but not necessarily the same size. The triangles are congruent if, in addition to this, their corresponding sides are of equal length.

The answers are:

Side XY = 26

BC ≅ XY

Side BC = 48

Answer:

isosceles triangle is the correct answer

hope it helps

it has two equal sides

Answer:

B

Step-by-step explanation:

Isoceles triangle is defined by two equal sides

Step-by-step explanation:

Mean of the origibal set = 20

No. of terms = 10

Sum = Mean x No. of terms

= 20 x 10 = 200

The sum of additional numbers to make the new set of observstion is 4 + 8 + 12...... + 40 = 220

New Sum = 200 + 220 = 420

The no of terms stay the same

New Mean = New Sum/ N

= 420/10

= 42

Answer:

4x=80 and 5x=100

Step-by-step explanation:

4x+5x=180

9x=180

1/9 (9x)=1/9 (180)

x=20

4(20)=80

5(20)=100

Answer:

Hope it will help. I did it.

Hope the image is clear.

Answer:

2

Step-by-step explanation:

__________________________

4x + 3y = 16

x = -3 / 4 y + 4

y = -4 / 3 x + 16 / 3

___________________________

y = x + 3

x = y - 3

y = x + 3

___________________________

Answer:

a) the probability of a length of stay greater than 10 hours is 0.03144

b) the length of stay is exceeded by 25% of the visits is 6.5 hrs

c)

P( X < 0 ) = 0.0559

The probability of length of stay less than 0 hours is 0.0559, length of stay cannot be less than 0. When the normal model is used, we assume that the LOF is approximately normally distributed.

The LOF is better modeled by the normal distribution near the mean and worse in the tails.

The probabilities in the left tail for the vales of X < 0  can be neglected.

Step-by-step explanation:

Given that;

mean μ = 4.6

standard deviation σ = 2.9

let x represent length of stay;

a. What is the probability of a length of stay greater than 10 hours?

p( x > 10 ) = p( x-μ/σ > 10-4.6 / 2.9 )

= p( Z > 1.86)

= P( Z < - 1.86 )

FROM THE Z SCORE TABLE;( Z < - 1.86 ) = 0.03144

p( x > 10 )  = 0.03144

Therefore, the probability of a length of stay greater than 10 hours is 0.03144

b) What length of stay is exceeded by 25% of the visits?

p( X > x ) = 0.25

so

p( X < x ) = 0.75

p( x-μ/σ < x-4.6 / 2.9 ) = 75

p( Z < x-4.6 / 2.9 ) = 0.75 ----- 1

also, from the standard normal table; P( Z < 0.67 ) = 0.75 ------ 11

from equation 1 and 11

x-4.6 / 2.9 = 0.67

x-4.6 = 2.9 × 0.67

x - 4.6 = 1.943

x = 4.6 + 1.943

x = 6.543 ≈ 6.5

Therefore, the length of stay is exceeded by 25% of the visits is 6.5 hrs

c)  From the normally distributed model, what is the probability of a length of stay less than 0 hours?

P( X < 0 ) = p( x-μ/σ < 0-4.6 / 2.9 )

= P( Z - 1.59)

from table;( Z - 1.59) = 0.0559

P( X < 0 ) = 0.0559

The probability of length of stay less than 0 hours is 0.0559, length of stay cannot be less than 0. When the normal model is used, we assume that the LOF is approximately normally distributed.

The LOF is better modeled by the normal distribution near the mean and worse in the tails.

The probabilities in the left tail for the vales of X < 0  can be neglected.  

Answer:

20,-25

Step-by-step explanation:

Answer:

19/6 u^3 v + v^2

Step-by-step explanation:

3uv2

u2−2v2+

5uv3

u2+3v2

=32

u3v+−2v2+53

u3v+3v2

Combine Like Terms:

=32

u3v+−2v2+53

u3v+3v2

= (3

u3v+

53

u3v)+(−2v2+3v2)

Answer:

8.75cm²

Step-by-step explanation:

First we need to find the angle subtended by the arc

L = theta/360 * 2pir

3.5 = theta/360 * 2*3.14(5)

3.5 = theta/360 * 31.4

theta/360 = 3.5/31.4

theta/360 = 0.11146

theta = 0.11146 * 360

theta = 40.13 degrees

Area of the sector = theta/360 * pir^2

Area of the sector = 40.13/360 * 3.14*25

Area of the sector = 40.13/360 * 78.5

Area of the sector  = 8.75cm

Hence the area of the sector is 8.75cm²

Answer:

Step-by-step explanation:

Part A: (3,2)

connect all the points on the paper

Part B: 5 units.  We know this since the x point for A is -2 and the point for B is 3.  -2 to 3(absolute value of -2 plus 3)= 5

Answer:

D

Step-by-step explanation:

z+nm is equiveland to mn+z since its the same equation but wrote in different positions.

Answer: the answer is D

Z + nm

Answer:

A

Step-by-step explanation:

you need find the smaller numbers of 10 which would be in answer A. all the other answers are bigger than 10

Answer:

$575

Step-by-step explanation

1150/2 = 575

Answer:

$1150

Step-by-step explanation:

because it is a buy one (for sale price), get one free

Answer:

8:3, or 8 to 3, or 3/6

Step-by-step explanation:

Answer:

8:3

Step-by-step explanation:

Answer:

05(9)+20

Step-by-step explanation:

becasue i know and this was the only way to allow me to give you the answer