1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
zubka84 [21]
3 years ago
15

When an opinion poll calls landline telephone numbers at random, approximately 30% of the numbers are working residential phone

numbers. The remainder are either non-residential, non-working, or computer/fax numbers. You watch the random dialing machine make 20 calls. What is the mean number of calls that reach a person? Standard deviation?
Mathematics
1 answer:
ioda3 years ago
8 0

Answer:

Mean = 6

Standard Deviation = 4.2

Step-by-step explanation:

This is a binomial probability distribution problem.

The mean has formula:

\mu = np

The standard deviation has formula:

\sigma=np(1-p)

Where n is the number of calls [20]

p is the probability of success [30=0.3]

Let's put these into the formula:

\mu=np\\\mu=(20)(0.3)\\\mu=6

and

\sigma=np(1-p)\\\sigma=(20)(0.3)(1-0.3)\\\sigma=(20)(0.3)(0.7)\\\sigma=4.2

You might be interested in
Locate the point (-3.5, -1) on the coordinate plane:
MrRissso [65]

Answer:

go to the left 3.5 units then go down one and that's your point

8 0
2 years ago
Read 2 more answers
An ipad is worth R1200, excluding 15% VAT. What is the selling price of the ipad including VAT
alukav5142 [94]

Answer:

R1,380

Step-by-step explanation:

The price of the iPad without VAT is R1200

We calculate 15% to get;

=  \frac{15}{100}  \times 1200

= 180

Now the selling price of the iPad including VAT

1200 + 180

= 1380

Therefore, the selling price of the ipad including VAT is R1380

7 0
3 years ago
Solve x2 + 5x = −6. x = 5 and x = 1 x = −5 and x = −1 x = 3 and x = 2 x = −3 and x = −2
fomenos

Answer:

x = −3 and x = −2

Step-by-step explanation:

x^2 + 5x = −6

Add 6 to each side

x^2 + 5x+6 = −6+6

x^2 +5x+6 =0

Factor

What 2 number multiply to 6 and add to 5

3*2 =6

3+2 =5

(x+3)(x+2) =0

Using the zero product property

x+3 =0             x+2 =0

x+3-3=0-3         x+2-2=0-2

x=-3                       x=-2

8 0
3 years ago
What is the answer to the 9s in 9,905,482
Otrada [13]
9 million and 9 hundred thousand

9,000,000
and 900,000
5 0
3 years ago
Solve 4x2−10x−6=0 using the Quadratic Formula.
vazorg [7]

Answer:

x=−1

x=−1.5

:DDDD

5 0
2 years ago
Other questions:
  • At an electronics store, a $165 television is marked up 110%. Trevor purchases the TV and must pay 6.5% sales tax.
    15·2 answers
  • Evaluate the expression: (x+y)2 when x=2 and y=-5​
    11·1 answer
  • You randomly choose one shirt from the shelves.<br> Find the probability of the event.
    7·2 answers
  • Can someone explain me Taales theorem?<br> pleasee
    12·1 answer
  • The substitution method solve 6x-y=3 4x+3y=1
    10·2 answers
  • Which expression can be used to determine the length of segment AB?
    13·1 answer
  • A sail is in the form of a right triangle that is four times as high as it is wide. The sail is made from 8 square meters of mat
    13·1 answer
  • F(x)=x-2; translation 5 units left
    5·1 answer
  • The admission fee at a county fair is $2 for children and $4 dollars for adults. Suppose that on the last day, 1600 people enter
    11·1 answer
  • What is the additive inverse for 4.5
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!