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If you want to find the probability that the mean of 50 customers is less than $60, the distribution to use is:

  • N ( 72 , 72 )
  • N ( 72 , 72 50 )
  • Exp ( 72 )
  • Exp ( 1 72 )

B: N ( 72 , 72 50 )

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The next three questions refer to the following situation:

The amount of time it takes a fourth grader to carry out the trash is uniformly distributed in the interval from 1 to 10 minutes.

What is the probability that a randomly chosen fourth grader takes more than 7 minutes to take out the trash?

  • 3 9
  • 7 9
  • 3 10
  • 7 10

A: 3 9

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Which graph best shows the probability that a randomly chosen fourth grader takes more than 6 minutes to take out the trash given that he/she has already taken more than 3 minutes?

D

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We should expect a fourth grader to take how many minutes to take out the trash?

  • 4.5
  • 5.5
  • 5
  • 10

B: 5.5

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The next three questions refer to the following situation:

At the beginning of the quarter, the amount of time a student waits in line at the campus cafeteria is normally distributed with a mean of 5 minutes and a standard deviation of 1.5 minutes.

What is the 90th percentile of waiting times (in minutes)?

  • 1.28
  • 90
  • 7.47
  • 6.92

D: 6.92

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The median waiting time (in minutes) for one student is:

  • 5
  • 50
  • 2.5
  • 1.5

A: 5

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Find the probability that the average wait time of 10 students is at most 5.5 minutes.

  • 0.6301
  • 0.8541
  • 0.3694
  • 0.1459

B: 0.8541

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A sample of 80 software engineers in Silicon Valley is taken and it is found that 20% of them earn approximately $50,000 per year. A point estimate for the true proportion of engineers in Silicon Valley who earn $50,000 per year is:

  • 16
  • 0.2
  • 1
  • 0.95

B: 0.2

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If P ( Z < z α ) = 0 . 1587 where Z ~ N ( 0 , 1 ) , then α is equal to:

  • -1
  • 0.1587
  • 0.8413
  • 1

A: -1

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A professor tested 35 students to determine their entering skills. At the end of the term, after completing the course, the same test was administered to the same 35 students to study their improvement. This would be a test of:

  • independent groups
  • 2 proportions
  • matched pairs, dependent groups
  • exclusive groups

C: matched pairs, dependent groups

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A math exam was given to all the third grade children attending ABC School. Two random samples of scores were taken.

n x ¯ s
Boys 55 82 5
Girls 60 86 7

Which of the following correctly describes the results of a hypothesis test of the claim, “There is a difference between the mean scores obtained by third grade girls and boys at the 5 % level of significance”?

  • Do not reject H o . There is insufficient evidence to conclude that there is a difference in the mean scores.
  • Do not reject H o . There is sufficient evidence to conclude that there is a difference in the mean scores.
  • Reject H o . There is insufficient evidence to conclude that there is no difference in the mean scores.
  • Reject H o . There is sufficient evidence to conclude that there is a difference in the mean scores.

D: Reject H o . There is sufficient evidence to conclude that there is a difference in the mean scores.

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In a survey of 80 males, 45 had played an organized sport growing up. Of the 70 females surveyed, 25 had played an organized sport growing up. We are interested in whether the proportion for males is higher than the proportion for females. The correct conclusion is:

  • There is insufficient information to conclude that the proportion for males is the same as the proportion for females.
  • There is insufficient information to conclude that the proportion for males is not the same as the proportion for females.
  • There is sufficient evidence to conclude that the proportion for males is higher than the proportion for females.
  • Not enough information to determine.

C: There is sufficient evidence to conclude that the proportion for males is higher than the proportion for females.

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Note: Chi-Square Test of a Single Variance; Not all classes cover this topic. From past experience, a statistics teacher has found that the average score on a midterm is 81 with a standard deviation of 5.2. This term, a class of 49 students had a standard deviation of 5 on the midterm. Do the data indicate that we should reject the teacher’s claim that the standard deviation is 5.2? Use α = 0.05 .

  • Yes
  • No
  • Not enough information given to solve the problem

B: No

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Note: F Distribution Test of ANOVA; Not all classes cover this topic. Three loading machines are being compared. Ten samples were taken for each machine. Machine I took an average of 31 minutes to load packages with a standard deviation of 2 minutes. Machine II took an average of 28 minutes to load packages with a standard deviation of 1.5 minutes. Machine III took an average of 29 minutes to load packages with a standard deviation of 1 minute. Find the p-value when testing that the average loading times are the same.

  • the p–value is close to 0
  • p–value is close to 1
  • Not enough information given to solve the problem

B: p-value is close to 1.

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The next three questions refer to the following situation:

A corporation has offices in different parts of the country. It has gathered the following information concerning the number of bathrooms and the number of employees at seven sites:

Number of employees x 650 730 810 900 102 107 1150
Number of bathrooms y 40 50 54 61 82 110 121

Is the correlation between the number of employees and the number of bathrooms significant?

  • Yes
  • No
  • Not enough information to answer question

B: No

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The linear regression equation is:

  • y ̂ = 0.0094 79.96 x
  • y ̂ = 79.96 + 0.0094 x
  • y ̂ = 79.96 - 0.0094 x
  • y ̂ = 0.0094 + 79.96 x

C: y ̂ = 79.96 x - 0.0094

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If a site has 1150 employees, approximately how many bathrooms should it have?

  • 69
  • 91
  • 91,954
  • We should not be estimating here.

D: We should not be estimating here.

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Note: Chi-Square Test of a Single Variance; Not all classes cover this topic. Suppose that a sample of size 10 was collected, with x = 4.4 and s = 1.4 .

H o : σ 2 = 1.6 vs. H a : σ 2 ≠ 1.6. Which graph best describes the results of the test?

A

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64 backpackers were asked the number of days their latest backpacking trip was. The number of days is given in the table below:

# of days 1 2 3 4 5 6 7 8
Frequency 5 9 6 12 7 10 5 10

Conduct an appropriate test to determine if the distribution is uniform.

  • The p–value is>0.10. There is insufficient information to conclude that the distribution is not uniform.
  • The p–value is<0.01. There is sufficient information to conclude the distribution is not uniform.
  • The p–value is between 0.01 and 0.10, but without alpha (α) there is not enough information
  • There is no such test that can be conducted.

A: The p–value is>0.10. There is insufficient information to conclude that the distribution is not uniform.

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­Note: F Distribution test of One-Way ANOVA; Not all classes cover this topic. Which of the following statements is true when using one-way ANOVA?

  • The populations from which the samples are selected have different distributions.
  • The sample sizes are large.
  • The test is to determine if the different groups have the same means.
  • There is a correlation between the factors of the experiment.

C: The test is to determine if the different groups have the same means.

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Questions & Answers

what is Economics
Ebem Reply
the branch of knowledge concerned with the production, consumption, and transfer of wealth and has Influence by sociology!!!!
Ajay
Economics is the study of how humans make decisions when they want to fulfil their requirements and desires for goods, services and resources.
Abdullah
Economics is the study how humans make decisions in the faces of scarcity.
Rose
economic is the study of how human make decision in the fact of scarcity.
Toang
Economics is a social science which study human behavior as a relationship between earn and scarce mean which have alternative uses
Juliet
what is market structure
Fatima
what is demand
Gooluck Reply
demand is the willingness to purchase something
Mohamed
demand is the potential ability or williness to purchases something at a particular price at a given period of time..
Ahmed
Demand refers to as quantities of a goods and services in which consumers are willing and able to purchase at a given period of time. Demand can also be defined as the desire backed by ability to purchase .
Fadiga
what is demand
John Reply
is the production of goods in scarcity
David
thanks
John
Demand refers to as quantities of a goods and services in which consumers are willing and able to purchase at a given period of time.
Fadiga
what is demand of supply
music Reply
What is the meaning of supply of labour
Anthonia Reply
what is production?
Elizabeth Reply
Production is basically the creation of goods and services to satisfy human wants
Anthonia
under what condition will demand curve slope upward from left to right instead of normally sloping downward from left to right
Atama Reply
how i can calculate elasticity?
Tewekel Reply
What is real wages
Emmanuella Reply
what are the concept of cost
Tabitha Reply
what is the difference between want and choice
Grace Reply
Want is a desire to have something while choice is the ability to select or choose a perticular good or services you desire to have at a perticular point in time.
Dalton
substitutes and complements
Amman Reply
Substitute are goods that can replace another good but complements goods that can be combined together
nkanyiso
account for persistent increase in lnflation
niwahereza Reply
what is opportunity cost
Adebowale Reply
opportunity cost reffered to as alternative foregone when choice is made
niwahereza
government measures to control inflation?
Formu Reply
control populationk growth rate by using family planning to reduce faster increase of people than job creation
niwahereza
in a comparison of the stages of meiosis to the stage of mitosis, which stages are unique to meiosis and which stages have the same event in botg meiosis and mitosis
Leah Reply
1 It is estimated that 30% of all drivers have some kind of medical aid in South Africa. What is the probability that in a sample of 10 drivers: 3.1.1 Exactly 4 will have a medical aid. (8) 3.1.2 At least 2 will have a medical aid. (8) 3.1.3 More than 9 will have a medical aid.
Nerisha Reply

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Source:  OpenStax, Collaborative statistics. OpenStax CNX. Jul 03, 2012 Download for free at http://cnx.org/content/col10522/1.40
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