Question 1

Let x be a binomial random variable with n=20 and p=.8.If we use the normal distribution to approximate probabilities for this,we would use a mean of ___.

Accepted Answer

A) 20 
B) 16 
C) 3.2 
D) 8 
E) 5 
A) 20 
B) 16 
C) 3.2 
D) 8 
E) 5

Question 2

Solve for probabilities in a continuous uniform distribution.

Accepted Answer

Probably the simplest of these distribut

Question 3

If x is uniformly distributed over the interval 8 to 12,inclusively (8 $\le$ x $\le$12),then the standard deviation of this distribution is ___.

Accepted Answer

A) 4.00 
B) 1.33 
C) 1.15 
D) 2.00 
E) 1.00 
A) 4.00 
B) 1.33 
C) 1.15 
D) 2.00 
E) 1.00

Question 4

The average time between phone calls arriving at a call centre is 30 seconds.Assuming that the time between calls is exponentially distributed,find the probability that more than a minute elapses between calls.

Accepted Answer

A) 0.135 
B) 0.368 
C) 0.865 
D) 0.607 
E) 0.709 
A) 0.135 
B) 0.368 
C) 0.865 
D) 0.607 
E) 0.709

Question 5

The expected (mean)life of a particular type of light bulb is 1,000 hours with a standard deviation of 50 hours.The life of this bulb is normally distributed.What is the probability that a randomly selected bulb would last fewer than 1100 hours?

Accepted Answer

A) 0.4772 
B) 0.9772 
C) 0.0228 
D) 0.5228 
E) 0.5513 
A) 0.4772 
B) 0.9772 
C) 0.0228 
D) 0.5228 
E) 0.5513

Question 6

Sure Stone Tire Company has established that the useful life of a particular brand of its automobile tires is normally distributed with a mean of 40,000 kilometres and a standard deviation of 5000 kilometres.What is the probability that a randomly selected tire of this brand has a life between 30,000 and 50,000 kilometres?

Accepted Answer

A) 0.5000 
B) 0.4772 
C) 0.9544 
D) 0.9772 
E) 1.0000 
A) 0.5000 
B) 0.4772 
C) 0.9544 
D) 0.9772 
E) 1.0000

Question 7

A normal distribution with a mean of zero and a standard deviation of 1 is called a null distribution.

Accepted Answer

A) True 
 B)False

Question 8

The expected (mean)life of a particular type of light bulb is 1,000 hours with a standard deviation of 50 hours.The life of this bulb is normally distributed.What is the probability that a randomly selected bulb would last fewer than 940 hours?

Accepted Answer

A) 0.3849 
B) 0.8849 
C) 0.1151 
D) 0.6151 
E) 0.6563 
A) 0.3849 
B) 0.8849 
C) 0.1151 
D) 0.6151 
E) 0.6563

Question 9

If x,the time (in minutes)to complete an oil change job at a certain auto station,is uniformly distributed over the interval 20 to 30,inclusively (20 $\le$ x $\le$ 30),then the probability that an oil change job is completed in less than or equal to 22 minutes,i.e. ,P(x $\le$ 22)is ___.

Accepted Answer

A) 0.200 
B) 0.300 
C) 0.000 
D) 0.250 
E) 1.000 
A) 0.200 
B) 0.300 
C) 0.000 
D) 0.250 
E) 1.000

Question 10

For an exponential distribution,the mean is always equal to its variance.

Accepted Answer

A) True 
 B)False

Question 11

If x is uniformly distributed over the interval 8 to 12,inclusively (8 $\le$ x $\le$ 12),then the height of this distribution,f(x),is ___.

Accepted Answer

A) 1/8 
B) 1/4 
C) 1/12 
D) 1/20 
E) 1/24 
A) 1/8 
B) 1/4 
C) 1/12 
D) 1/20 
E) 1/24

Question 12

Let z be a normal random variable with mean 0 and standard deviation 1.The 50th percentile of z is ___.

Accepted Answer

A) 0.6700 
B) -1.254 
C) 0.0000 
D) 1.2800 
E) 0.5000 
A) 0.6700 
B) -1.254 
C) 0.0000 
D) 1.2800 
E) 0.5000

Question 13

If x is uniformly distributed over the interval 8 to 12,inclusively (8 $\le$ x $\le$ 12),then P(x < 7)is ___.

Accepted Answer

A) 0.500 
B) 0.000 
C) 0.375 
D) 0.250 
E) 1.000 
A) 0.500 
B) 0.000 
C) 0.375 
D) 0.250 
E) 1.000

Question 14

Within a range of z scores from -2 to +2,you can expect to find ___ per cent of the values in a normal distribution.

Accepted Answer

A) 95 
B) 99 
C) 68 
D) 34 
E) 100 
A) 95 
B) 99 
C) 68 
D) 34 
E) 100

Question 15

Solve for probabilities in a normal distribution using z scores and for the mean,the standard deviation,or a value of x in a normal distribution when given information about the area under the normal curve.

Accepted Answer

The most widely used of all distribution

Question 16

If x,the time (in minutes)to complete an oil change job at a certain auto service station,is uniformly distributed over the interval 20 to 30,inclusively (20 $\le$ x $\le$ 30),then the probability that an oil change job is completed in 25 to 28 minutes,inclusively,i.e. ,P(25 $\le$ x $\le$ 28)is ___.

Accepted Answer

A) 0.250 
B) 0.500 
C) 0.300 
D) 0.750 
E) 81.000 
A) 0.250 
B) 0.500 
C) 0.300 
D) 0.750 
E) 81.000

Question 17

If x is uniformly distributed over the interval 8 to 12,inclusively (8 $\le$ x $\le$ 12),then the probability,P(10.0 $\le$ x $\le$ 11.5),is ___.

Accepted Answer

A) 0.250 
B) 0.333 
C) 0.375 
D) 0.500 
E) 0.750 
A) 0.250 
B) 0.333 
C) 0.375 
D) 0.500 
E) 0.750

Question 18

The average time between phone calls arriving at a call centre is 30 seconds.Assuming that the time between calls is exponentially distributed,find the probability that less than two minutes elapse between calls.

Accepted Answer

A) 0.018 
B) 0.064 
C) 0.936 
D) 0.982 
E) 1.000 
A) 0.018 
B) 0.064 
C) 0.936 
D) 0.982 
E) 1.000

Let x be a binomial random variable with n=20 and p=.8.If we use the normal distribution to approximate probabilities for this,we would use a mean of ___.

Solve for probabilities in a continuous uniform distribution.

If x is uniformly distributed over the interval 8 to 12,inclusively (8 $\le$ x $\le$ 12),then the standard deviation of this distribution is ___.

The average time between phone calls arriving at a call centre is 30 seconds.Assuming that the time between calls is exponentially distributed,find the probability that more than a minute elapses between calls.

The expected (mean)life of a particular type of light bulb is 1,000 hours with a standard deviation of 50 hours.The life of this bulb is normally distributed.What is the probability that a randomly selected bulb would last fewer than 1100 hours?

A normal distribution with a mean of zero and a standard deviation of 1 is called a null distribution.

The expected (mean)life of a particular type of light bulb is 1,000 hours with a standard deviation of 50 hours.The life of this bulb is normally distributed.What is the probability that a randomly selected bulb would last fewer than 940 hours?

If x,the time (in minutes)to complete an oil change job at a certain auto station,is uniformly distributed over the interval 20 to 30,inclusively (20 $\le$ x $\le$ 30),then the probability that an oil change job is completed in less than or equal to 22 minutes,i.e. ,P(x $\le$ 22)is ___.

For an exponential distribution,the mean is always equal to its variance.

If x is uniformly distributed over the interval 8 to 12,inclusively (8 $\le$ x $\le$ 12),then the height of this distribution,f(x),is ___.

Let z be a normal random variable with mean 0 and standard deviation 1.The 50^th percentile of z is ___.

If x is uniformly distributed over the interval 8 to 12,inclusively (8 $\le$ x $\le$ 12),then P(x < 7)is ___.

Within a range of z scores from -2 to +2,you can expect to find ___ per cent of the values in a normal distribution.

Solve for probabilities in a normal distribution using z scores and for the mean,the standard deviation,or a value of x in a normal distribution when given information about the area under the normal curve.

If x,the time (in minutes)to complete an oil change job at a certain auto service station,is uniformly distributed over the interval 20 to 30,inclusively (20 $\le$ x $\le$ 30),then the probability that an oil change job is completed in 25 to 28 minutes,inclusively,i.e. ,P(25 $\le$ x $\le$ 28)is ___.

If x is uniformly distributed over the interval 8 to 12,inclusively (8 $\le$ x $\le$ 12),then the probability,P(10.0 $\le$ x $\le$ 11.5),is ___.

The average time between phone calls arriving at a call centre is 30 seconds.Assuming that the time between calls is exponentially distributed,find the probability that less than two minutes elapse between calls.

Introduction to Statistics

Charts and Graphs

Descriptive Statistics

Probability

Discrete Distributions

Sampling and Sampling Distributions

Statistical Inference: Estimation for Single Populations

Statistical Inference: Hypothesis Testing for Single Populations

Statistical Inferences About Two Populations

Analysis of Variance and Design of Experiments

Simple Regression Analysis and Correlation

Multiple Regression Analysis

Building Multiple Regression Models

Time-Series Forecasting and Index Numbers

Analysis of Categorical Data

Nonparametric Statistics

Statistical Quality Control

Decision Analysis

Filters

Exam 6: Continuous Distributions

Let x be a binomial random variable with n=20 and p=.8.If we use the normal distribution to approximate probabilities for this,we would use a mean of ___.

Solve for probabilities in a continuous uniform distribution.

If x is uniformly distributed over the interval 8 to 12,inclusively (8 ≤\le≤ x ≤\le≤ 12),then the standard deviation of this distribution is ___.

The average time between phone calls arriving at a call centre is 30 seconds.Assuming that the time between calls is exponentially distributed,find the probability that more than a minute elapses between calls.

The expected (mean)life of a particular type of light bulb is 1,000 hours with a standard deviation of 50 hours.The life of this bulb is normally distributed.What is the probability that a randomly selected bulb would last fewer than 1100 hours?

A normal distribution with a mean of zero and a standard deviation of 1 is called a null distribution.

The expected (mean)life of a particular type of light bulb is 1,000 hours with a standard deviation of 50 hours.The life of this bulb is normally distributed.What is the probability that a randomly selected bulb would last fewer than 940 hours?

If x,the time (in minutes)to complete an oil change job at a certain auto station,is uniformly distributed over the interval 20 to 30,inclusively (20 ≤\le≤ x ≤\le≤ 30),then the probability that an oil change job is completed in less than or equal to 22 minutes,i.e. ,P(x ≤\le≤ 22)is ___.

For an exponential distribution,the mean is always equal to its variance.

If x is uniformly distributed over the interval 8 to 12,inclusively (8 ≤\le≤ x ≤\le≤ 12),then the height of this distribution,f(x),is ___.

Let z be a normal random variable with mean 0 and standard deviation 1.The 50th percentile of z is ___.

If x is uniformly distributed over the interval 8 to 12,inclusively (8 ≤\le≤ x ≤\le≤ 12),then P(x < 7)is ___.

Within a range of z scores from -2 to +2,you can expect to find ___ per cent of the values in a normal distribution.

Solve for probabilities in a normal distribution using z scores and for the mean,the standard deviation,or a value of x in a normal distribution when given information about the area under the normal curve.

If x is uniformly distributed over the interval 8 to 12,inclusively (8 ≤\le≤ x ≤\le≤ 12),then the probability,P(10.0 ≤\le≤ x ≤\le≤ 11.5),is ___.

The average time between phone calls arriving at a call centre is 30 seconds.Assuming that the time between calls is exponentially distributed,find the probability that less than two minutes elapse between calls.

Introduction to Statistics

Charts and Graphs

Descriptive Statistics

Probability

Discrete Distributions

Sampling and Sampling Distributions

Statistical Inference: Estimation for Single Populations

Statistical Inference: Hypothesis Testing for Single Populations

Statistical Inferences About Two Populations

Analysis of Variance and Design of Experiments

Simple Regression Analysis and Correlation

Multiple Regression Analysis

Building Multiple Regression Models

Time-Series Forecasting and Index Numbers

Analysis of Categorical Data

Nonparametric Statistics

Statistical Quality Control

Decision Analysis

Filters

If x is uniformly distributed over the interval 8 to 12,inclusively (8 $\le$ x $\le$ 12),then the standard deviation of this distribution is ___.

If x,the time (in minutes)to complete an oil change job at a certain auto station,is uniformly distributed over the interval 20 to 30,inclusively (20 $\le$ x $\le$ 30),then the probability that an oil change job is completed in less than or equal to 22 minutes,i.e. ,P(x $\le$ 22)is ___.

If x is uniformly distributed over the interval 8 to 12,inclusively (8 $\le$ x $\le$ 12),then the height of this distribution,f(x),is ___.

Let z be a normal random variable with mean 0 and standard deviation 1.The 50^th percentile of z is ___.

If x is uniformly distributed over the interval 8 to 12,inclusively (8 $\le$ x $\le$ 12),then P(x < 7)is ___.

If x is uniformly distributed over the interval 8 to 12,inclusively (8 $\le$ x $\le$ 12),then the probability,P(10.0 $\le$ x $\le$ 11.5),is ___.