answer.
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
Debora [2.8K]
1 year ago
15

According to a Wired magazine article, of e-mails that are received are tracked using software that can tell the e-mail sender w

hen, where, and on what type of device the e-mail was opened (Wired magazine website). Suppose we randomly select received e-mails.

Mathematics
1 answer:
VladimirAG [237]1 year ago
8 0

Answer:

a. 12

b. 7.200 and 2.683

Step-by-step explanation:

The computation is shown below:

Given that

P = 0.40 and n = 30

a)

The expected value of received e-mails is

= n × p

= 30 × 0.4

= 12  

b)

The variance of emails received is

= n × p × (1 - p)

= 30 × 0.4 × 0.6

= 7.200

Now

The standard deviation of emails received is

= sqrt(variance)

= 2.683

We simply applied the above formula

You might be interested in
Gene starts from home and travels 3 miles north to the shopping mall. From the shopping mall, he travels 2 miles west to the lib
Alex73 [517]

Answer: The largest angle formed during his trip is at the mall between his home and the library.

Step-by-step explanation:

Hi, since the situation forms a right triangle (see image attached) the angle formed between his home and the library is 90°.

The sum of the interior angles of a right triangle is 180°, and the right angle (90°)is the largest angle formed.

So, the largest angle formed during his trip is at the mall between his home and the library.

Feel free to ask for more if needed or if you did not understand something.

7 0
1 year ago
Read 2 more answers
In an analysis of healthcare data, ages have been rounded to the nearest multiple of 5 years. The difference between the true ag
Mars2501 [29]

Answer:

The approximate probability that the mean of the rounded ages within 0.25 years of the mean of the true ages is P=0.766.

Step-by-step explanation:

We have a uniform distribution from which we are taking a sample of size n=48. We have to determine the sampling distribution and calculate the probability of getting a sample within 0.25 years of the mean of the true ages.

The mean of the uniform distribution is:

\mu=\dfrac{Max+Min}{2}=\dfrac{2.5+(-2.5)}{2}=0

The standard deviation of the uniform distribution is:

\sigma=\dfrac{Max-Min}{\sqrt{12}}=\dfrac{2.5-(-2.5)}{\sqrt{12}}=\dfrac{5}{3.46}=1.44

The sampling distribution can be approximated as a normal distribution with the following parameters:

\mu_s=\mu=0\\\\\sigma_s=\dfrac{\sigma}{\sqrt{n}}=\dfrac{1.44}{\sqrt{48}}=\dfrac{1.44}{6.93}=0.21

We can now calculate the probability that the sample mean falls within 0.25 from the mean of the true ages using the z-score:

z=\dfrac{X-\mu}{\sigma}=\dfrac{0.25-0}{0.21}=\dfrac{0.25}{0.21}=1.19\\\\\\P(|X_s-\mu|

7 0
1 year ago
The first terms of an infinite geometric sequence, Un are 2, 6, 18, 54... The first terms of a second infinite geometric sequenc
gladu [14]

Answer:

r = 9 and m = 112

Step-by-step explanation:

\sum_{k=1}^{225}W_{k}=\sum_{k=0}^{m}4r^{k}

Write W in terms of U and V.

\sum_{k=1}^{225}(U_{k}+V_{k})=\sum_{k=0}^{m}4r^{k}\\\sum_{k=1}^{225}U_{k}+\sum_{k=1}^{225}V_{k}=\sum_{k=0}^{m}4r^{k}

Define U and V using geometric series formula.

\sum_{k=1}^{225}2(3)^{k-1}+\sum_{k=1}^{225}2(-3)^{k-1}=\sum_{k=0}^{m}4r^{k}

Use sum of geometric series formula.

2(\frac{1-(3)^{225}}{1-3})+2(\frac{1-(-3)^{225}}{1-(-3)})=4(\frac{1-(r)^{m+1}}{1-r})

Simplify.

-1(1-3^{225})+\frac{1+3^{225}}{2}=4(\frac{1-(r)^{m+1}}{1-r})\\-1+3^{225}+\frac{1}{2}+\frac{3^{225}}{2}=4(\frac{1-(r)^{m+1}}{1-r})\\-\frac{1}{2}+\frac{3(3^{225})}{2}=4(\frac{1-(r)^{m+1}}{1-r})\\\frac{-1+3(3^{225})}{2}=4(\frac{1-(r)^{m+1}}{1-r})\\\frac{-1+3^{226}}{2}=4(\frac{1-(r)^{m+1}}{1-r})\\4\frac{-1+3^{226}}{8}=4(\frac{1-(r)^{m+1}}{1-r})\\4\frac{1-3^{226}}{-8}=4(\frac{1-(r)^{m+1}}{1-r})\\4\frac{1-9^{113}}{1-9}=4(\frac{1-(r)^{m+1}}{1-r})

Therefore, r = 9 and m = 112.

8 0
1 year ago
1. WHEELS Zack is designing wheels for a concept car.
mars1129 [50]

Answer:

9 inches

Step-by-step explanation:

Diameter=D

Radius=R

D=(2)R

(18)=(2)R

18/2=2/2 R

9=R

4 0
1 year ago
Jolyn, a golfer, claims that her drive distance is not equal to 222 meters, on average. Several of her friends do not believe he
Troyanec [42]

Answer:

0.29

Step-by-step explanation:

z-score is given by the formula:

z=(μ-M)/σ where

  • μ is the hypothesis drive distance, which is 222
  • M is the mean sample drive distance
  • σ is the standard deviation of the sample drive distance

Therefore

z=(222-218)/14≈0.29

3 0
2 years ago
Other questions:
  • Mike and Ike are experts at pitching horseshoes. 70% of Mike's tosses are ringers. 67% of Ike's tosses are ringers. Suppose Mike
    15·1 answer
  • The director of marketing at a large company wants to determine if the amount of money spent on internet marketing is a good pre
    9·1 answer
  • Christy spent $500 over her budget on gifts during the holidays. In addition to her regular job, she took a part-time job at the
    10·1 answer
  • Solve the recurrence relation: hn = 5hn−1 − 6hn−2 − 4hn−3 + 8hn−4 with initial values h0 = 0, h1 = 1, h2 = 1, and h3 = 2 using (
    8·1 answer
  • What value of n makes the equation true? -1/5n + 7 =2
    7·2 answers
  • Suppose that the prevalence of a certain type of tree allergy is 0.26 in the general population. If 100 people randomly chosen f
    11·2 answers
  • A portfolio consisting of four stocks is expected to produce returns of minus9%, 11%, 13% and 17%, respectively, over the next f
    13·1 answer
  • Daniel wants to predict how far he can hike based on the time he spends on the hike. He collected some data on
    10·2 answers
  • Which value of x would make LK ∥ OM? x = 2 x = 2.4 x = 4.8 x = 8
    11·1 answer
  • 19,432÷x=48 Remainder 232 (Plz help its for my hw that's due tmrw)
    14·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!