PLEASE HELP I DON'T UNDERSTAND!!!!!! I WILL MARK!!!!!!!!!!!!!!

The drying times for a certain type of cement are normally distributed with a standard deviation of 30 minutes. A researcher wis

IceJOKER [234]

Answer:

h. 36

Step-by-step explanation:

For a 68.26% confidence, z = 1.0.

Standard deviation (s) = 30 minutes

The sample size needed to assure that the sample mean does not differ from the true mean by more than 5 minutes is given by:

$5\geq z*\frac{s}{\sqrt n}\\\sqrt n\geq 1*\frac{30}{5}\\n\geq 36$

The sample size needed is 36.

5 0

3 years ago

For the problem below, θ is a central angle in a circle of a radius r. Find the length of arc s cut off by θ.

mixas84 [53]

Answer:

Here, we will use the formula from trigonometry which defines a radian

we know that an angle is a radian when the length of the radius of the circle is equal to the length of the arc formed

hence, if the radius is r and the arc is r, the angle (in radians) will be 1

if the radius is r and the arc is 2r, the angle in radians will be equal to:

length of arc / radius = 2r/r = 2 radians

I believe this will explain what is actually happening in these type of questions

So, the equation:

Θ(in radians) = s / r (where the length of arc is s and the radius is r)

π/4 = s / 12

s = 3π or 9.42 inches

4 0

3 years ago

Which set of ordered pairs could represent a function? (2, 3), (2, 2), (2, 4), (2, 9), (2, –2) (1, 5), (2, 6), (1, 6), (4, 5), (

Ratling [72]

Given:

The set of ordered pairs in the options:

(a) (2, 3), (2, 2), (2, 4), (2, 9), (2, –2)

(b) (1, 5), (2, 6), (1, 6), (4, 5), (1, 4)

(c) (1, 0), (2, 0), (1, 3), (4, 3), (5, 7)

(d) (5, 1), (7, 3), (9, 5), (11, 7), (13, 9)

To find:

The set of ordered pairs that could represent a function.

Solution:

A set of ordered pairs represent a function, if there exist unique output (y-value) for each input (x-value).

In option (a) we have, five output values y=3,2,4,9,-2 for single input x=2. So, it is not a function.

In option (b) we have, three output values y=5,6,4 for single input x=1. So, it is not a function.

In option (c) we have, two output values y=0,3 for single input x=1. So, it is not a function.

In option (d), all inputs has unique output.

Therefore, the correct option is (d).

4 0

3 years ago

Read 2 more answers

Given that a function, g, has a domain of -1 ≤ x ≤ 4 and a range of 0 ≤ g(x) ≤ 18 and that g(-1) = 2 and g(2) = 8, select the st

notka56 [123]

Options

(A)g(5) = 12
(B)g(1) = -2
(C)g(2) = 4
(D)g(3) = 18

Answer:

(D)g(3) = 18

Step-by-step explanation:

Given that the function, g, has a domain of -1 ≤ x ≤ 4 and a range of 0 ≤ g(x) ≤ 18 and that g(-1) = 2 and g(2) = 8

Then the following properties must hold

The value(s) of x must be between -1 and 4
The values of g(x) must be between 0 and 18.
g(-1)=2
g(2)=9

We consider the options and state why they are true or otherwise.

Option A: g(5)=12

The value of x=5. This contradicts property 1 stated above. Therefore, it is not true.

Option B: g(1) = -2

The value of g(x)=-2. This contradicts property 2 stated above. Therefore, it is not true.

Option C: g(2) = 4

The value of g(2)=4. However by property 4 stated above, g(2)=9. Therefore, it is not true.

Option D: g(3) = 18

This statement can be true as its domain is in between -1 and 4 and its range is in between 0 and 18.

Therefore, Option D could be true.

3 0

4 years ago

Construct 3 linear equation starting with qiven solution z = 1/3

Andreyy89

Answer:

(a) $9z+2=5$

(b) $21z-11=-4$

(c) $4z=2-2z$

Step-by-step explanation:

We are required to construct 3 linear equations starting with the given solution z = 1/3.

Equation 1

$z=\frac{1}{3}$

Multiply both sides by 9

$9z=\frac{1}{3}\times 9\\9z=3$

Rewrite 3 as 5-2

9z=5-2

Add 2 to both sides

Our first equation is: $9z+2=5$

Equation 2

$z=\frac{1}{3}$

Multiply both sides by 21

$21z=\frac{1}{3}\times 21\\21z=7$

Rewrite 7 as 11-4

21z=11-4

Subtract 11 from both sides

Our second equation is: $21z-11=-4$

Equation 3

$z=\frac{1}{3}$

Multiply both sides by 6

$6z=\frac{1}{3}\times 6\\6z=2$

Rewrite 6z as 4z+2z

4z+2z=2

Subtract 2z from both sides

Our third equation is: $4z=2-2z$

4 0

3 years ago