Question 1

Z is a standard normal random variable.What is the value of Z if the area between -Z and Z is 0.754?

Accepted Answer

A) 0.377 
B) 0.123 
C) 2.16 
D) 1.16 
A) 0.377 
B) 0.123 
C) 2.16 
D) 1.16 D

Question 2

Exhibit 6-1
The assembly time for a product is uniformly distributed between 6 to 10 minutes.
-Refer to Exhibit 6-1.The probability of assembling the product between 7 to 9 minutes is

Accepted Answer

A) zero 
B) 0.50 
C) 0.20 
D) 1 
A) zero 
B) 0.50 
C) 0.20 
D) 1 B

Question 3

The average price of cell phones manufactured by Ahmadi,Inc.is $98 with a standard deviation of $12.Furthermore,it is known that the prices of the cell phones manufactured by Ahmadi are normally distributed.
a.What percentage of cell phones produced by Ahmadi,Inc.will have prices of at least $120.20?
b.Cell phones with prices of at least 81.80 will get a free gift.What percentage of the cell phones will be eligible for the free gift?
c.What are the minimum and the maximum values of the middle 95% of cell phone prices?
d.If 7,218 of the Ahmadi cell phones were priced at least $119.00,how many cell phones were produced by Ahmadi,Inc.?

Accepted Answer

a.3.13%
b.91.15%
c.Minimum Price 74.48 Maximum Price $121.52
d.180,000

Question 4

The uniform,normal,and exponential distributions are

Accepted Answer

A) all continuous probability distributions 
B) all discrete probability distributions 
C) can be either continuous or discrete,depending on the data 
D) all the same distributions 
A) all continuous probability distributions 
B) all discrete probability distributions 
C) can be either continuous or discrete,depending on the data 
D) all the same distributions

Question 5

The records show that 8% of the items produced by a machine do not meet the specifications.Use the normal approximation to the binomial distribution to answer the following questions.What is the probability that a sample of 100 units contains
a.Five or more defective units?
b.Ten or fewer defective units?
c.Eleven or less defective units?

Accepted Answer

a.0.9015
b

Question 6

A professor at a local community college noted that the grades of his students were normally distributed with a mean of 74 and a standard deviation of 10.The professor has informed us that 6.3 percent of his students received A's while only 2.5 percent of his students failed the course and received F's.
a.What is the minimum score needed to make an A?
b.What is the maximum score among those who received an F?
c.If there were 5 students who did not pass the course,how many students took the course?

Accepted Answer

The answer of A professor at a local community college...

Question 7

The weekly earnings of bus drivers are normally distributed with a mean of $395.If only 1.1 percent of the bus drivers have a weekly income of more than $429.35,what is the value of the standard deviation of the weekly earnings of the bus drivers?

Accepted Answer

Standard D

Question 8

A random variable X is uniformly distributed between 45 and 150.
a.Determine the probability of X = 48.
b.What is the probability of X$\le$60?
c.What is the probability of X$\ge$50?
d.Determine the expected vale of X and its standard deviation.

Accepted Answer

a.0.000
b.

Question 9

Exhibit 6-10
A professor at a local university noted that the grades of her students were normally distributed with a mean of 73 and a standard deviation of 11.
-Refer to Exhibit 6-10.If 69.5 percent of the students received grades of C or better,what is the minimum score of those who received C's?

Accepted Answer

A) 70.39 
B) 67.39 
C) 50.39 
D) 65.39 
A) 70.39 
B) 67.39 
C) 50.39 
D) 65.39

Question 10

The driving time for an individual from his home to his work is uniformly distributed between 300 to 480 seconds.
a.Determine the probability density function.
b.Compute the probability that the driving time will be less than or equal to 435 seconds.
c.Determine the expected driving time.
d.Compute the variance.
e.Compute the standard deviation.

Accepted Answer

a.b.0.75
c

Question 11

Exhibit 6-8
The life expectancy of a particular brand of tire is normally distributed with a mean of 40,000 and a standard deviation of 5,000 miles.
-Refer to Exhibit 6-8.What is the probability that a randomly selected tire will have a life of exactly 47,500 miles?

Accepted Answer

A) 0.0000 
B) 0.9332 
C) 0.0668 
D) 0.4993 
A) 0.0000 
B) 0.9332 
C) 0.0668 
D) 0.4993

Question 12

Z is a standard normal random variable.What is the value of Z if the area to the right of Z is 0.9803?

Accepted Answer

A) -2.06 
B) 0.4803 
C) 0.0997 
D) 3.06 
A) -2.06 
B) 0.4803 
C) 0.0997 
D) 3.06

Question 13

For a standard normal distribution,the probability of obtaining a z value between -1.9 to 1.7 is

Accepted Answer

A) 0.9267 
B) 0.4267 
C) 1.4267 
D) 0.5000 
A) 0.9267 
B) 0.4267 
C) 1.4267 
D) 0.5000

Question 14

The average starting salary of this year's graduates of a large university (LU)is $25,000 with a standard deviation of $5,000.Furthermore,it is known that the starting salaries are normally distributed.
a.What is the probability that a randomly selected LU graduate will have a starting salary of at least $31,000?
b.Individuals with starting salaries of less than $12,200 receive a low income tax break.What percentage of the graduates will receive the tax break?
c.What are the minimum and the maximum starting salaries of the middle 95% of the LU graduates?
d.If 68 of the recent graduates have salaries of at least $35,600,how many students graduated this year from this university?

Accepted Answer

a.0.1151
b

Question 15

The highest point of a normal curve occurs at

Accepted Answer

A) one standard deviation to the right of the mean 
B) two standard deviations to the right of the mean 
C) approximately three standard deviations to the right of the mean 
D) the mean 
A) one standard deviation to the right of the mean 
B) two standard deviations to the right of the mean 
C) approximately three standard deviations to the right of the mean 
D) the mean

Question 16

Scores on a recent national statistics exam were normally distributed with a mean of 80 and a standard deviation of 6.
a.What is the probability that a randomly selected exam will have a score of at least 71?
b.What percentage of exams will have scores between 89 and 92?
c.If the top 2.5% of test scores receive merit awards,what is the lowest score eligible for an award?
d.If there were 334 exams with scores of at least 89,how many students took the exam?

Accepted Answer

a..9332
b.

Question 17

Exhibit 6-3
Consider the continuous random variable X,which has a uniform distribution over the interval from 20 to 28.
-Refer to Exhibit 6-3.The probability that X will take on a value between 21 and 25 is

Accepted Answer

A) 0.125 
B) 0.250 
C) 0.500 
D) 1.000 
A) 0.125 
B) 0.250 
C) 0.500 
D) 1.000

Question 18

Exhibit 6-6
The starting salaries of individuals with an MBA degree are normally distributed with a mean of $40,000 and a standard deviation of $5,000.
-Refer to Exhibit 6-6.What percentage of MBA's will have starting salaries of $34,000 to $46,000?

Accepted Answer

A) 38.49% 
B) 38.59% 
C) 50% 
D) 76.98% 
A) 38.49% 
B) 38.59% 
C) 50% 
D) 76.98%

Question 19

Exhibit 6-8
The life expectancy of a particular brand of tire is normally distributed with a mean of 40,000 and a standard deviation of 5,000 miles.
-Refer to Exhibit 6-8.What is the probability that a randomly selected tire will have a life of at least 47,500 miles?

Accepted Answer

A) 0.4332 
B) 0.9332 
C) 0.0668 
D) 0.4993 
A) 0.4332 
B) 0.9332 
C) 0.0668 
D) 0.4993

Question 20

The average starting salary of this year's MBA students is $35,000 with a standard deviation of $5,000.Furthermore,it is known that the starting salaries are normally distributed.What are the minimum and the maximum starting salaries of the middle 95% of MBA graduates?

Accepted Answer

Min.= 25,2

Z is a standard normal random variable.What is the value of Z if the area between -Z and Z is 0.754?

Exhibit 6-1 The assembly time for a product is uniformly distributed between 6 to 10 minutes. -Refer to Exhibit 6-1.The probability of assembling the product between 7 to 9 minutes is

The uniform,normal,and exponential distributions are

The weekly earnings of bus drivers are normally distributed with a mean of $395.If only 1.1 percent of the bus drivers have a weekly income of more than $429.35,what is the value of the standard deviation of the weekly earnings of the bus drivers?

A random variable X is uniformly distributed between 45 and 150. a.Determine the probability of X = 48. b.What is the probability of X $\le$ 60? c.What is the probability of X $\ge$ 50? d.Determine the expected vale of X and its standard deviation.

Exhibit 6-10 A professor at a local university noted that the grades of her students were normally distributed with a mean of 73 and a standard deviation of 11. -Refer to Exhibit 6-10.If 69.5 percent of the students received grades of C or better,what is the minimum score of those who received C's?

Exhibit 6-8 The life expectancy of a particular brand of tire is normally distributed with a mean of 40,000 and a standard deviation of 5,000 miles. -Refer to Exhibit 6-8.What is the probability that a randomly selected tire will have a life of exactly 47,500 miles?

Z is a standard normal random variable.What is the value of Z if the area to the right of Z is 0.9803?

For a standard normal distribution,the probability of obtaining a z value between -1.9 to 1.7 is

The highest point of a normal curve occurs at

Exhibit 6-3 Consider the continuous random variable X,which has a uniform distribution over the interval from 20 to 28. -Refer to Exhibit 6-3.The probability that X will take on a value between 21 and 25 is

Exhibit 6-6 The starting salaries of individuals with an MBA degree are normally distributed with a mean of $40,000 and a standard deviation of $5,000. -Refer to Exhibit 6-6.What percentage of MBA's will have starting salaries of $34,000 to $46,000?

Exhibit 6-8 The life expectancy of a particular brand of tire is normally distributed with a mean of 40,000 and a standard deviation of 5,000 miles. -Refer to Exhibit 6-8.What is the probability that a randomly selected tire will have a life of at least 47,500 miles?

The average starting salary of this year's MBA students is $35,000 with a standard deviation of $5,000.Furthermore,it is known that the starting salaries are normally distributed.What are the minimum and the maximum starting salaries of the middle 95% of MBA graduates?

Data and Statistics

Descriptive Statistics: Tabular and Graphical Presentations

Descriptive Statistics: Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

Hypothesis Tests

Statistical Inference About Means and Proportions With Two Populations

Inferences About Population Variances

Tests of Goodness of Fit and Independence

Analysis of Variance and Experimental Design

Simple Linear Regression

Multiple Regression

Regression Analysis: Model Building

Index Numbers

Forecasting

Nonparametric Methods

Statistical Methods for Quality Control

Decision Analysis

Sample Survey

Filters

Exam 6: Continuous Probability Distributions

Z is a standard normal random variable.What is the value of Z if the area between -Z and Z is 0.754?

Exhibit 6-1 The assembly time for a product is uniformly distributed between 6 to 10 minutes. -Refer to Exhibit 6-1.The probability of assembling the product between 7 to 9 minutes is

The uniform,normal,and exponential distributions are

The weekly earnings of bus drivers are normally distributed with a mean of $395.If only 1.1 percent of the bus drivers have a weekly income of more than $429.35,what is the value of the standard deviation of the weekly earnings of the bus drivers?

A random variable X is uniformly distributed between 45 and 150. a.Determine the probability of X = 48. b.What is the probability of X ≤\le≤ 60? c.What is the probability of X ≥\ge≥ 50? d.Determine the expected vale of X and its standard deviation.

Exhibit 6-10 A professor at a local university noted that the grades of her students were normally distributed with a mean of 73 and a standard deviation of 11. -Refer to Exhibit 6-10.If 69.5 percent of the students received grades of C or better,what is the minimum score of those who received C's?

Exhibit 6-8 The life expectancy of a particular brand of tire is normally distributed with a mean of 40,000 and a standard deviation of 5,000 miles. -Refer to Exhibit 6-8.What is the probability that a randomly selected tire will have a life of exactly 47,500 miles?

Z is a standard normal random variable.What is the value of Z if the area to the right of Z is 0.9803?

For a standard normal distribution,the probability of obtaining a z value between -1.9 to 1.7 is

The highest point of a normal curve occurs at

Exhibit 6-3 Consider the continuous random variable X,which has a uniform distribution over the interval from 20 to 28. -Refer to Exhibit 6-3.The probability that X will take on a value between 21 and 25 is

Exhibit 6-6 The starting salaries of individuals with an MBA degree are normally distributed with a mean of $40,000 and a standard deviation of $5,000. -Refer to Exhibit 6-6.What percentage of MBA's will have starting salaries of $34,000 to $46,000?

Exhibit 6-8 The life expectancy of a particular brand of tire is normally distributed with a mean of 40,000 and a standard deviation of 5,000 miles. -Refer to Exhibit 6-8.What is the probability that a randomly selected tire will have a life of at least 47,500 miles?

The average starting salary of this year's MBA students is $35,000 with a standard deviation of $5,000.Furthermore,it is known that the starting salaries are normally distributed.What are the minimum and the maximum starting salaries of the middle 95% of MBA graduates?

Data and Statistics

Descriptive Statistics: Tabular and Graphical Presentations

Descriptive Statistics: Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

Hypothesis Tests

Statistical Inference About Means and Proportions With Two Populations

Inferences About Population Variances

Tests of Goodness of Fit and Independence

Analysis of Variance and Experimental Design

Simple Linear Regression

Multiple Regression

Regression Analysis: Model Building

Index Numbers

Forecasting

Nonparametric Methods

Statistical Methods for Quality Control

Decision Analysis

Sample Survey

Filters

A random variable X is uniformly distributed between 45 and 150. a.Determine the probability of X = 48. b.What is the probability of X $\le$ 60? c.What is the probability of X $\ge$ 50? d.Determine the expected vale of X and its standard deviation.