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Anika [276]
3 years ago
11

A professor using an open source introductory statistics book predicts that 10% of the students will purchase a hard copy of the

book, 55% will print it out from the web, and 35% will read it online. At the end of the semester he asks his students to complete a survey where they indicate what format of the book they used. Of the 200 students, 25 said they bought a hard copy of the book, 85 said they printed it out from the web, and 90 said they read it online.
Mathematics
1 answer:
34kurt3 years ago
3 0

Answer:

12.5% bought a hard copy. 42.5% printed it from the web. And 45% read it online.

Step-by-step explanation: Since there are 200 students in total, think of 200 as 100% of students. You would divide 25/200 which equals 0.125 then multiply 0.125 times 100 which is 12.5 or 12.5%. Same process with the other numbers (85/200)x100=42.5   (90/200)x100=45. Hope this is what the question was asking

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A company surveyed adult Americans about their consumer debt. They reported that 48% of Millennials (those born between 1980 and
sergeinik [125]

Answer:

We reject H₀ at 95 % of CI the group of Gen Xers who do not pay their credit card each month, is greater than this proportion for Millennians

Step-by-step explanation:

Sample proportion 1: Born between 1980 and 1996

sample size    n₁  = 450

p₁  =  0,48        p₁ = 48 %

x₁ = 0,48 * 450        x₁ = 216

Sample proportion 2:  Born between 1965 and 1971

sample size    n₂  = 300

p₂ =  0,60         p₂ = 60%

x₂  = 0,6* 300     x₂  = 180

Test Hypothesis:

Null Hypothesis                          H₀               p₂  =   p₁

Alternative Hypothesis              H                p₂  >  p₁

Samples both big enough to use the normal distribution as an approximation to the binomial distribution.

We assume  CI = 95 %   then significance level α   = 5 %  the alternative hypothesis tells us that we need to develop a one-tail test to the right.

z-score  is z(c)  for  α = 0,05       from z-table   z(c) = 1,64

To calculate z(s)

z(s)  =  ( p₂  -  p₁ ) / √ p*q ( 1 /n₁ + 1 / n₂)

p₂ - p₁  =  0,60  - 0,48

p₂ - p₁  =  0,12

p = ( x₁ + x₂ ) / n₁ + n₂

p = ( 216  + 300) / 450 + 300

p = 516 / 750     p = 0,688      then   q = 1 - p     q = 0,312

z(s) = 0,12 / √ 0,688*0,312* ( 1/450) + 1/ 300)

z(s) = 0,12 / √ 0,2146* ( 0,0022 + 0,0033)

z(s) = 0,12 / √ 0,001192

z(s) = 0,12/ 0,03452

z(s) = 3,47

Comparing |z(c)|   and |z(s)|

z(s) > z(c)

Then z(s) is in the rejection region. We reject H₀.

We can support the  claim that the proportion of the group Gen Xers who do not pay their credit card is greater than Millennians

6 0
3 years ago
Liza is playing a game in which she earns 3 points for each correct response but loses 2 points for each incorrect response. She
ella [17]
Number 2 is the correct answer! 
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7 0
3 years ago
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Five candy bars cost $4.32 or eight candy bars cost $6.48. Which is a better buy?
Citrus2011 [14]

Answer:

C

Step-by-step explanation:

4.32/5=0.86 per bar

6.48/8=0.81 per bar <---- better buy

6 0
3 years ago
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HEEEEELLLPPPP!!! I really need this to be answered im soo confused!!
Marysya12 [62]

Answer:

C

Step-by-step explanation:

∠ AFD = ∠ AFC + ∠ CFD

Given ∠ CFA = 90° and

∠ CFD = 90° - ∠ EFD, that is

∠ CFD = 90° - 62° = 28°, thus

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4 0
3 years ago
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What is the value of f?
laiz [17]

Answer:

f(1/2) = -2

General Formulas and Concepts:

<u>Pre-Algebra</u>

Order of Operations: BPEMDAS

  1. Brackets
  2. Parenthesis
  3. Exponents
  4. Multiplication
  5. Division
  6. Addition
  7. Subtraction
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<u>Algebra I</u>

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Step-by-step explanation:

<u>Step 1: Define</u>

f(x) = 8x - 6

f(1/2) is x = 1/2

<u>Step 2: Evaluate</u>

  1. Substitute in <em>x</em>:                    f(1/2) = 8(1/2) - 6
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3 years ago
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