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
Aleksandr [31]
3 years ago
13

When an opinion poll selects cell phone numbers at random to dial, the cell phone exchange is first selected and then random dig

its are added to form a complete telephone number. When using this procedure to generate random cell phone numbers, approximately 55%55% of the cell numbers generated correspond to working numbers. You watch a pollster dial 1515cell numbers that have been selected in this manner.What is the mean number of calls that reach a working cell number?A. 0.550.55B. 1515C. 8.258.25D. 3030
Mathematics
1 answer:
Sav [38]3 years ago
6 0

Answer:

A

Step-by-step explanation:

When an opinion poll selects cell phone numbers at random to dial, the cell phone exchange is first selected and then random digits are added to form a complete telephone number. When using this procedure to generate random cell phone numbers, approximately 55%55% of the cell numbers generated correspond to working numbers. You watch a pollster dial 1515cell numbers that have been selected in this manner.What is the mean number of calls that reach a working cell number?A. 0.550.55B. 1515C. 8.258.25D. 3030

You might be interested in
Which of the following shapes contain perpendicular line segments?
Lina20 [59]

Answer:

y

Step-by-step explanation:

I know because I am smart

4 0
2 years ago
Read 2 more answers
Plzzzzzzzzzzzzzzzzzzzz
Salsk061 [2.6K]

Answer:

B

Step-by-step explanation:

I graphed the equation, and the highest point was at 3.7 feet in the air, 4 seconds into the flight. See the graph below. Hope this helps!

8 0
3 years ago
A consensus forecast is the average of a large number of individual analysts' forecasts. Suppose the individual forecasts for a
zaharov [31]

Answer:

a) P(X>3.5)=P(\frac{X-\mu}{\sigma}>\frac{3.5-\mu}{\sigma})=P(Z>\frac{3.5-5}{1.2})=P(z>-1.25)

And we can find this probability using the complement rule:

P(z>-1.25)=1-P(z

b) P(X

And we can find this probability uing the normal standard table:

P(z

c) P(3.5

And we can find this probability with this difference:

P(-1.25

And in order to find these probabilities we can use tables for the normal standard distribution, excel or a calculator.  

P(-1.25

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".  

Part a

Let X the random variable that represent the variable of interest of a population, and for this case we know the distribution for X is given by:

X \sim N(5,1.2)  

Where \mu=5 and \sigma=1.2

We are interested on this probability

P(X>3.5)

And the best way to solve this problem is using the normal standard distribution and the z score given by:

z=\frac{x-\mu}{\sigma}

If we apply this formula to our probability we got this:

P(X>3.5)=P(\frac{X-\mu}{\sigma}>\frac{3.5-\mu}{\sigma})=P(Z>\frac{3.5-5}{1.2})=P(z>-1.25)

And we can find this probability using the complement rule:

P(z>-1.25)=1-P(z

Part b

We are interested on this probability

P(X

And the best way to solve this problem is using the normal standard distribution and the z score given by:

z=\frac{x-\mu}{\sigma}

If we apply this formula to our probability we got this:

P(X

And we can find this probability uing the normal standard table:

P(z

Part c

P(3.5

And we can find this probability with this difference:

P(-1.25

And in order to find these probabilities we can use tables for the normal standard distribution, excel or a calculator.  

P(-1.25

3 0
3 years ago
Work varies directly with the
irinina [24]

Answer:

yes

Step-by-step explanation:

no

6 0
2 years ago
5000 rounded to the nearest 10 thousand
Serga [27]
It only thousand you can't rounded to ten thousand
6 0
3 years ago
Other questions:
  • "if one of the 255 subjects is randomly selected, find the probability that the person is over 40 years of age or that they drin
    12·2 answers
  • Find inequality represented in the graph someone please help
    13·1 answer
  • Find<br> ∫^[infinity]_-[infinity] xe^-x^2 dx.
    12·1 answer
  • Plz help me and show work plz
    9·1 answer
  • Can somebody please help me :(
    9·1 answer
  • A photograph is 25 cm wide and 20 am high. it must be reduced to fit a space that is 8 cm high. find the width of the reduced ph
    12·1 answer
  • Tính giá trị 2a+ 3=? với a=1
    11·1 answer
  • Need help extra points and mark brainlist
    6·2 answers
  • Helpppp meee pleaseeeeeeeeee!!!’
    12·2 answers
  • Help 50 pointsss pleasssse
    8·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!