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
kompoz [17]
3 years ago
11

A programmer plans to develop a new software system. In planning for the operating system that he will use, he needs to estimate

the percentage of computers that use a new operating system. How many computers must be surveyed in order to be 95% confident that his estimate is in error by no more than two percentage points? a)Assume that nothing is known about the percentage of computers with new operating systems.
Mathematics
2 answers:
lawyer [7]3 years ago
8 0

Answer: 2401

Step-by-step explanation:

Formula to find the sample size is given by :-

n= p(1-p)(\dfrac{z_{\alpha/2}}{E})^2

, where p = prior population proportion.

z_{\alpha/2} = Two -tailed z-value for {\alpha

E= Margin of error.

As per given , we have

Confidence level : 1-\alpha=0.95

⇒\alpha=1-0.95=0.05

Two -tailed z-value for \alpha=0.05 : z_{\alpha/2}=1.96

E= 2%=0.02

We assume that nothing is known about the percentage of computers with new operating systems.

Let us take p=0.5  [we take p= 0.5 if prior estimate of proportion is unknown.]

Required sample size will be :-

n= 0.5(1-0.5)(\dfrac{1.96}{0.02})^2\\\\ 0.25(98)^2=2401

Hence, the number of computer must be surveyed = 2401

Digiron [165]3 years ago
4 0

<em>Answer:</em>

<em>n = 1067</em>

<em>Step-by-step explanation:</em>

<em />

<em>Since nothing is known, we would assume that 50% of the computers use the new operating system. </em>

<em>So, standard error = 0.5/SQRT(n) </em>

<em>Z-value for a 95% CI = 1.9596 </em>

<em>So, margin of error = 1.9596 x 0.5 / SQRT(n) = 0.03 </em>

<em>So, n = 1067 (approx.)</em>

<em />

<em>This will be your approximate answer : n = 1067</em>

You might be interested in
A soccer ball is kicked from 3 feet above the ground. the height,h, in feet of the ball after t seconds is given by the function
dexar [7]
Here's our equation.

h=-16t+64t+3

We want to find out when it returns to ground level (h = 0)

To find this out, we can plug in 0 and solve for t.

0 = -16t+64t+3 \\ 16t-64t-3=0 \\ use\ the\ quadratic\ formula\ \frac{-b\±\sqrt{b^2-4ac}}{2a}  \\ \frac{-(-64)\±\sqrt{(-64)^2-4(16)(-3)}}{2*16}  = \frac{64\±\sqrt{4096+192}}{32}

= \frac{64\±\sqrt{4288}}{32} = \frac{64\±8\sqrt{67}}{32} = \frac{8\±\sqrt{67}}{4} = \boxed{\frac{8+\sqrt{67}}{4}\ or\ 2-\frac{\sqrt{67}}{4}}

So the ball will return to the ground at the positive value of \boxed{\frac{8+\sqrt{67}}{4}} seconds.

What about the vertex? Simple! Since all parabolas are symmetrical, we can just take the average between our two answers from above to find t at the vertex and then plug it in to find h!

\frac{1}2(\frac{8+\sqrt{67}}{4}+2-\frac{\sqrt{67}}{4}) = \frac{1}2(2+\frac{\sqrt{67}}{4}+2-\frac{\sqrt{67}}{4}) = \frac{1}2(4) = 2

h=-16t^2+64t+3 \\ h=-16(2)^2+64(2)+3 \\ \boxed{h=67}


8 0
3 years ago
One pound of grapes costs $1.55. Which equation correctly shows a pair of equivalent ratios that can be used to find the cost of
stira [4]

Answer:

StartFraction 1.55 over 1 EndFraction = StartFraction x over 3.5 EndFraction

Step-by-step explanation:

\frac{1.55}{1}  =  \frac{x}{3.5}  \\  \\  \therefore \: x = 1.55 \times 3.5 \\  \\ \therefore \: x = \$ 5.425 \\  \\\therefore \: x\approx  \$5.43

4 0
3 years ago
Read 2 more answers
If U-235 has a half-life of 713 million years and the age of the sample is 2.631 billion years old then how many half-lifes has
lutik1710 [3]
<span>As the age of the U-235 sample is 2.631 billion years, and the half-life of U-235 is 713 million years, the sample has undergone 2.361 X 1,000,000,000 / 713 X 1,000,000 = 3.69 half lives. In each half-life the sample reduces to half its original weight according to the radioactive Half-Life Formula: ln (Nt /N0) = -kt, where N0 = mass of the original weight of radioactive material, Nt = mass of radioactive material at time t, k = decay constant and t = time interval . We have to put Nt/N0 = 1/2 for time interval = half-life.</span>
8 0
3 years ago
Read 2 more answers
Which number line represents the solution set for the end equality 3x &lt; -9
shepuryov [24]

divide both sides by 3

so, you'll get x<-3

that's your solution

4 0
3 years ago
Please help ASAP if you know how. Thanks so much
zlopas [31]
I’m not so sure i’m sorry
6 0
3 years ago
Read 2 more answers
Other questions:
  • Rosalie earns extra money by working as a babysitter over the weekend. She charges $10 to drive to the home and an additional $8
    10·1 answer
  • Help homework is due today. please
    11·1 answer
  • Which ordered pair represents the y-intercept of the graph of the equation y= -4x - 7
    7·1 answer
  • Which of the following is an equivalent form of the compound inequality −33 &gt; −3x − 6 ≥ −6?
    14·1 answer
  • Mrs.Brown gives two tests to her class. 30% of the class passed both tests and 45% of the class passed the first test. What perc
    15·1 answer
  • Simplify x+ -4x + -3
    15·2 answers
  • Below are two parallel lines with a third line intersecting them. Help me on this Geometry transversal angle!!​
    11·1 answer
  • ONE HUNDRED POINT AND BRAINIEST FOR BEST CORRCET ANSWER! PLS HELP ASAP! Cami is comparing the growth rates in the value of two i
    10·1 answer
  • On a driving test, Roxane answered 70% of the 20 questions correctly. How many questions did
    15·2 answers
  • •** Plss help me **•
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!