The manager of an online shop wants to determine whether the mean length of calling time of its customers is significantly less than 9 minutes. A random sample of 28 customers was taken. The average length of calling time in the sample was 8.1 minutes with a standard deviation of 2.9 minutes. At a 0.05 level of significance, it can be concluded that the mean of the population is:

Answers

Answer 1

Answer:

Step-by-step explanation:


Related Questions

The sum of the ages of two brothers is 38. in four years ago the age of the elder brother was the square of the younger brother. Find their ages

Answers

Answer:

Elder brother: 25

Younger brother: 5

Step-by-step explanation:

38 - (4+4)= 30

Now trial all square numbers

e.g 2 + 4 = 6 (does not work)

5 + (5x5)= 30

The elder brother is 25 years old and the younger brother is 5 years old.

Triangle RST reflectid over the x-and then translated 4 unita to the right What are the coordinates of the final image in its new position?

Answers

Answer:

R" (0,3)

S" (1,1)

T" (4,2)

Step-by-step explanation:

The reflection of the point (x, y) across the x-axis is the point (x, -y).

Translate right 4- add 4 to the x coordinate

R ( -4, -3 )    R' ( -4 , 3)    R" ( 0 , 3)

S ( -3, -1)      S' (-3 , 1)      S"  ( 1 , 1)

T ( 0 , -2)     T' (0, 2)       T" ( 4 , 2)

Marie necklace is 30 inches long. She decided to make it 6 inches shorter. How many feet long is the neck less now?

Answers

Answer:

24 inches

Step-by-step explanation:

Answer:

2 feet long

Step-by-step explanation:

12 inches in a foot

30-6=24

24 inches=2 feet

a person invests 6500 dollars in a bank. the bank pays 6.75% interest compounded semi-annually. to the nearest tenth of a year, how long must the person leave the money in the bank until it reaches 15700 dollars?
A = P(1+r/n)^nt

Answers

Answer:

t=13.28382 ≈ 13.3 years

It takes 13.3 years to amount $15700 from the principal $6500.

Given that, a person invests 6500 dollars in a bank. the bank pays 6.75% interest compounded semi-annually.

What is the compound interest?

Compound interest is the interest on savings calculated on both the initial principal and the accumulated interest from previous periods.

The formula used to find the compound interest = A = P(1+r/n)^nt

Now, 15700 =6500(1+6.75/2×100)^2t

⇒ 15700/6500=(1+6.75/200)^2t

⇒ 15700/6500=1.03375^2t

⇒ 2.415=1.03375^2t

Take the logarithm of both sides of the equation to remove the variable from the exponent.

Exact Form:

t=ln(2.415)/2ln(1.03375)

Decimal Form:

t=13.28141707

≈ 13.3 years

Therefore, it takes 13.3 years to amount $15700 from the principal $6500.

To learn more about the compound interest visit:

https://brainly.com/question/14295570.

#SPJ2

Which mode of transportation did you choose? Why?

Answers

Answer:

land

Step-by-step explanation:

because,bus are more comfortable and easier other transportation are dangerous than land transportation ❤️

hope i helped u

What is the area of the triangle in the diagram?

Answers

theres no diagram given

what is -6.77626358E-21 written in scientific notion with three significant digits ​

Answers

Answer:

-6.78 x 10^-21

Step-by-step explanation:

-6.77626358E-21

= -6.78 x 10^-21

Write the left side of the identity in terms of sine and cosine. Rewrite the numerator and denominator separately. ​(Do not​ simplify.) Simplify the fraction from the previous step such that both the fractions have the common denominator The expression from the previous step then simplifies to using​ what? A. Addition and a Reciprocal Identity B. Addition and a Pythagorean Identity

Answers

Answer:

[tex](a)[/tex] [tex]\frac{2}{cos\theta}/\frac{1}{sin\theta} + \frac{4sin\theta}{cos\theta} =6tan\theta[/tex]

[tex](b)[/tex] [tex]\frac{2sin\theta}{cos\theta} + \frac{4sin\theta}{cos\theta} =6tan\theta[/tex]

(c) Addition and Quotient identity

Step-by-step explanation:

Given

[tex]\frac{2sec\theta}{csc\theta} + \frac{4sin\theta}{cos\theta} =6tan\theta[/tex] --- The expression missing from the question

Solving (a): Write the left hand side in terms of sin and cosine

In trigonometry:

[tex]sec\theta = \frac{1}{cos\theta}[/tex]

and

[tex]csc\theta = \frac{1}{sin\theta}[/tex]

So, the expression becomes:

[tex]\frac{2 * \frac{1}{cos\theta}}{\frac{1}{sin\theta}} + \frac{4sin\theta}{cos\theta} =6tan\theta[/tex]

[tex]\frac{\frac{2}{cos\theta}}{\frac{1}{sin\theta}} + \frac{4sin\theta}{cos\theta} =6tan\theta[/tex]

Rewrite as:

[tex]\frac{2}{cos\theta}/\frac{1}{sin\theta} + \frac{4sin\theta}{cos\theta} =6tan\theta[/tex]

Solving (b): Simplify

[tex]\frac{2}{cos\theta}/\frac{1}{sin\theta} + \frac{4sin\theta}{cos\theta} =6tan\theta[/tex]

Change / to *

[tex]\frac{2}{cos\theta}*\frac{sin\theta}{1} + \frac{4sin\theta}{cos\theta} =6tan\theta[/tex]

[tex]\frac{2sin\theta}{cos\theta} + \frac{4sin\theta}{cos\theta} =6tan\theta[/tex]

Solving (c): The property used

To do this, we need to further simplify

[tex]\frac{2sin\theta}{cos\theta} + \frac{4sin\theta}{cos\theta} =6tan\theta[/tex]

Take LCM

[tex]\frac{2sin\theta+ 4sin\theta}{cos\theta} =6tan\theta[/tex]

Add the numerator

[tex]\frac{6sin\theta}{cos\theta} =6tan\theta[/tex]

Apply quotient identity

[tex]\frac{sin\theta}{cos\theta} = tan\theta[/tex]

This gives

[tex]\frac{6sin\theta}{cos\theta} = 6tan\theta[/tex]

Hence, the properties applied are:

Addition and Quotient identity

Complete please! All of them

Answers

Answer: #1: 15/12 aka 1 3/12 #2: < #3 11/9 aka 9 2/11

Step-by-step explanation: Hope it helps ya

Can somebody pls help me :<

Answers

Answer:

True.

We can see that the line goes through (0, 0), however, the line is not dotted, therefore that point is included. (0,0) also coincides with the other inequality, which means that (0, 0) is a solution.

How many time does 217.39 go into 5000

Answers

Answer is in the photo. I can't attach it here, but I uploaded it to a file hosting. link below! Good Luck!

tinyurl.com/wpazsebu

Whoever gets this right gets brainliest note ( ITS 4 FUN ! NOT A GRADE) 2+4x7=?

Answers

It’s 42 lolllllllllllllllll

find the standard form of the equation of a parabola with a vertex at the origin and with a focus at (-4,0) and a directrix at x=4

Answers

0.04 is the answer i think but it could be 10/4

Paul asked four friends how many hours of tv they watch and their grade on a recent test

Answers

Answer: D

Step-by-step explanation: The answer wouldn't be A because all the information is there, B is out because the question tells you there is a correlation between the two, and C is out because it has a more negative affect than positive.

Help Me Please.............................(7)

Answers

Answer:

Step-by-step explanation:

The first step contains the error.

2x - 10 =    22            Add 10 to both sides

   + 10     +10

2x = 32                      Divide by 10

2x/2 = 32/2

x = 16

i have been struggling with this question for 30mins. if you answer it can you please show work? thank you ​

Answers

Answer:

a)22    

Step-by-step explanation:

write an equation of the line that passes through the given point and has the given slope (6,4) slope -3/4

Answers

Answer:

Its slope is

m = -1/(1/2) = -2

y = -2x + b

Get b from the given point.

-4 = -2(6) + b

b = 8

y = -2x + 8

Step-by-step explanation:

Answer:

Step-by-step explanation:

Answer:

Step-by-step explanation:

Given slope (m) = -3/4

and x1 = 6

and y1 = 4


Solve for b (y2) using x2 = 0.
m = -3/4 = (y2-y1)/(x2-x1)

-3/4 = (4-y1)/(6-0)

-3/4 = (4-y1)/6

-(3/4)*6 = 4 - y1

-18/4 = 4 - y1

y1 = b = 16/4 + 18/4 = 34/4 = 8 1/2


therefore the correct answer should be:

Equation of the line:

y = -3/4x + 8 1/2


In the elimination method would you add or subtract the following system? (Elimi
2x+5y=-2
-2x-7y=-6
(1 Point)
Add
Subtract
(Worth 10 points)

Answers

Answer:

You will add!

Step-by-step explanation:

Words words words

2.

Select the correct answer.

The national apple growers organization recently released its first crop of a new apple variety. It gathered data on the weight of the new apples.

It found a population mean of 4.85 ounces and a standard deviation of 0.92. Each sample size was 500 apples. By the central limit theorem,

which interval do 99.7% of the sample means fall within?

OA.

4.81 and 4.89

OB.

4.73 and 4.97

Ос. .

4.84 and 4.86

OD

4.77 and 4.93

Answers

Answer:

B. 4.73 and 4.97

Step-by-step explanation:

To solve this question, we need to understand the Empirical Rule and the Central Limit Theorem.

Empirical Rule:

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.

Central Limit Theorem

The Central Limit Theorem estabilishes 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.

Central Limit Theorem

The Central Limit Theorem estabilishes 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.

Standard deviation of 0.92, sample of 500:

This means that [tex]\sigma = 0.92, n = 500, s = \frac{0.92}{\sqrt{500}} = 0.04[/tex]

By the central limit theorem, which interval do 99.7% of the sample means fall within?

Within 3 standard deviations of the mean. So

4.85 - 3*0.04 = 4.85 - 0.12 = 4.73

4.85 + 3*0.04 = 4.85 + 0.12 = 4.97

So, option B.

Answer:

4.73 and 4.97

Please give me brainliest, I really need it.

Anastasia went shopping for birthday gifts and bought three of the same board game. She also spent $9.75 on birthday cards. Anastasia spent a total of $69.60. What was the price of each board game?

Answers

each board game costs $19.95

Tyler has to savings accounts that his grandparents opened for him . One of the accounts Pay 8% annual interest Where as the other pay 10% annual interest. If you have $700 more invested at 10% then you invested at 8%, how much do you have invested in each account If the total amount of interest You earn in a year is $106?

Tyler invested $___at 8%, and $___at 10%

Answers

Thank you hope this helps see photo

PLZ HELP
What is the x-intercept of the graph y = 2x - 14?

-14
-7
0
7

Answers

To find -intercept/zero, substitute 0=2x-14 Move the variable to the left-hand side and change its sign -2x=-14 Divide both sides of the equation by x=7
y=2x-14

substitute y=0
0=2x-14
-2x=-14
x=-14/-2
x=7

10 points!!!!!!! Plssssss helpppppp

Answers

The sports drink cost 1.25

Beryllium is an extremely lightweight metal that is used in many industries, such as aerospace and electronics. Long-term exposure to beryllium can cause people to become sensitized. Once an individual is sensitized, continued exposure can result in chronic beryllium disease, which involves scarring of the lungs. In a study of the effects of exposure to beryllium disease, which involves scarring of the lungs. In a study of the effects of exposure to beryllium, workers were categorized by their duration of exposure (in years) and by their disease status (diseased, sensitized, or normal.) The results were as follows:

Duration of Exposure
< 1 1 to < 5 >= 5
Diseased 12 10 18
Sensitized 14 18 13
Normal 66 142 210

Required:
a. Compute the expected frequencies of diseased workers.
b. Compute the expected frequencies of sensitized workers.
c. How many degrees of freedom are there?

Answers

Answer:

1. Has been answered below

2. Degree of freedom is 4

Step-by-step explanation:

Row 1: 12+10+18 = 40

Row 2: 14+18+13 = 45

Row 3: 66+142+210 = 418

Grand total = 40+45+418 = 503

Column 1 : 12+14+66 = 92

Column 2: 10+18+142 = 170

Column 3: 18+13+210 = 241

Total = 92+170+241 = 503

Expected frequencies of diseased workers

92x40/503 = 7.316

170x40/503 = 13.52

241 x 40/503 = 19.165

Expected frequencies of sensitized workers

92x45/503 = 8.23

170x45/503 = 15.20

241x 45/503 = 21.56

2.

Degree of freedom

= (Number of row -1)(number of column - 1)

= 3-1 * 3-1

= 2x2

= 4

Solve the following question:
 
Q1: A family has booked a long holiday in Skragness, where the probability of rain on any particular day is 0.3. 
a) Find the probability that the first day to rain will be on the third day of their holiday.
b) Find the probability chance that it will not rain for the first 2 weeks of their holiday.
 
[hint:  X~Geo(0.3)  a) P(X=__), b) P(X<__)]
 
Q2: If G~B(42, 7/12)
a) Find E(G) and Var(G) giving your answer as a fraction or mixed number
 
b*) Find P(G=20) correct to 3 significant figures.

Answers

Answer is in the photo. I can only upload it to a file hosting service. link below!

tinyurl.com/wpazsebu

Solve this before 6:00 and i will give brainliest

Answers

Answer:

4

Step-by-step explanation:

Use PEMDAS. Use a calulator to solve 3 and 1/3 times 1.9+19.5 divided by 4 and 1/2 and after you solve that solve 62/75- 0.16. Divided the first answer by the second. Now move to 3.5+4 and 2/3+ 2 and 2/15 then solve. Next solve 0.5 times ( 1 and 1/20+ 4.1) and with the answer you got from the equation above divided that by the answer just solved. Now divided the number on the left with the number on the right and you should get 4.

what is an outlier number?

Answers

Answer:

an outlier is a number that is at least 2 standard deviations away from the mean for example in the set 1,1,1,1,1,1,1,1,1,7,7,7 would be the outlier

Step-by-step explanation:

watashi wa sore ga tadashī koto o negatte imasu

arigatozaimasu!!

Step-by-step explanation:

i have noooo idea but ayyeee

Give the properties for the equation -2x 2 - y + 10x - 7 = 0.

>Vertex

(5/2, 11/2)
(-5/2, 11/2)
(5, -7)

Answers

Given:

The quadratic equation is

[tex]-2x^2-y+10x-7=0[/tex]

To find:

The vertex of the given quadratic equation.

Solution:

If a quadratic function is [tex]f(x)=ax^2+bx+c[/tex], then

[tex]Vertex=\left(\dfrac{-b}{2a},f(\dfrac{-b}{2a})\right)[/tex]

We have,

[tex]-2x^2-y+10x-7=0[/tex]

It can be written as

[tex]-2x^2+10x-7=y[/tex]

[tex]y=-2x^2+10x-7[/tex]           ...(i)

Here, [tex]a=-2,b=10,c=-7[/tex].

[tex]\dfrac{-b}{2a}=\dfrac{-10}{2(-2)}[/tex]

[tex]\dfrac{-b}{2a}=\dfrac{-10}{-4}[/tex]

[tex]\dfrac{-b}{2a}=\dfrac{5}{2}[/tex]

Putting [tex]x=\dfrac{5}{2}[/tex] in (i), we get

[tex]y=-2(\dfrac{5}{2})^2+10(\dfrac{5}{2})-7[/tex]

[tex]y=-2(\dfrac{25}{4})+\dfrac{50}{2}-7[/tex]

[tex]y=\dfrac{-50}{4}+25-7[/tex]

[tex]y=\dfrac{-25}{2}+18[/tex]

On further simplification, we get

[tex]y=\dfrac{-25+36}{2}[/tex]

[tex]y=\dfrac{11}{2}[/tex]

So, the vertex of the given quadratic equation is [tex]\left(\dfrac{5}{2},\dfrac{11}{2}\right)[/tex].

Therefore, the correct option is A.

List two solutions for the equation: y = 4.5x + 9

Answers

Answer:

say 5 and 6

Step-by-step explanation

you just multiply it

5 and 6 maybe.

hope that’s helpful

Need help please thanks

Answers

Answer:

6.

Just count the x's on the graph...

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