# Complete Short Stats Quizzes

*label*Mathematics

*timer*Asked: Nov 1st, 2018

*account_balance_wallet*$10

**Question description**

COMPLETE EACH QUIZ ON SEPARATE WORD DOCUMENT

CHOOSE THE CORRECT MULTIPLE CHOICE ANSWER

QUIZ 3:

### QUESTION 1

A numerical description of the outcome of an experiment is called a

descriptive statistic | ||

probability function | ||

variance | ||

random variable |

5 points

### QUESTION 2

A random variable that can assume only a finite number of values is referred to as a(n)

infinite sequence | ||

finite sequence | ||

discrete random variable | ||

discrete probability function |

5 points

### QUESTION 3

A random variable that may take on any value in an interval or collection of intervals is known as a

continuous random variable | ||

discrete random variable | ||

continuous probability function | ||

finite probability function |

5 points

### QUESTION 4

A description of the distribution of the values of a random variable and their associated probabilities is called a

probability distribution | ||

random variance | ||

random variable | ||

expected value |

5 points

### QUESTION 5

The expected value for a binomial probability distribution is

E(x) = Pn(1 - n) | ||

E(x) = P(1 - P) | ||

E(x) = nP | ||

E(x) = nP(1 - P) |

5 points

### QUESTION 6

The variance for the binomial probability distribution is

var(x) = P(1 - P) | ||

var(x) = nP | ||

var(x) = n(1 - P) | ||

var(x) = nP(1 - P) |

5 points

### QUESTION 7

Which of the following is not a characteristic of an experiment where the binomial probability distribution is applicable?

the experiment has a sequence of n identical trials | ||

exactly two outcomes are possible on each trial | ||

the trials are dependent | ||

the probabilities of the outcomes do not change from one trial to another |

5 points

### QUESTION 8

The number of electrical outages in a city varies from day to day. Assume that the number of electrical outages (x) in the city has the following probability distribution.

x f(x)

0 0.80

1 0.15

2 0.04

3 0.01

The mean and the standard deviation for the number of electrical outages (respectively) are

2.6 and 5.77 | ||

0.26 and 0.577 | ||

3 and 0.01 | ||

0 and 0.8 |

5 points

### QUESTION 9

The center of a normal curve is

always equal to zero | ||

is the mean of the distribution | ||

cannot be negative | ||

is the standard deviation |

5 points

### QUESTION 10

A normal distribution with a mean of 0 and a standard deviation of 1 is called

a probability density function | ||

an ordinary normal curve | ||

a standard normal distribution | ||

none of these alternatives is correct |

5 points

### QUESTION 11

A negative value of Z indicates that

the number of standard deviations of an observation is to the right of the mean | ||

the number of standard deviations of an observation is to the left of the mean | ||

a mistake has been made in computations, since Z cannot be negative | ||

the data has a negative mean |

10 points

### QUESTION 12

Which of the following is not a characteristic of the normal probability distribution?

The mean, median, and the mode are equal | ||

The mean of the distribution can be negative, zero, or positive | ||

The distribution is symmetrical | ||

The standard deviation must be 1 |

10 points

### QUESTION 13

Z is a standard normal random variable. The P (1.41 ≤ Z ≤ 2.85) equals

0.4978 | ||

0.4207 | ||

0.9185 | ||

0.0771 |

10 points

### QUESTION 14

X is a normally distributed random variable with a mean of 8 and a standard deviation of 4. The probability that X is between 1.48 and 15.56 is

0.0222 | ||

0.4190 | ||

0.5222 | ||

0.9190 |

10 points

### QUESTION 15

Larger values of the standard deviation result in a normal curve that is

shifted to the right | ||

shifted to the left | ||

narrower and more peaked | ||

wider and flatter |

QUIZ 4:

### QUESTION 1

Parameters are

numerical characteristics of a sample | ||

numerical characteristics of a population | ||

the averages taken from a sample | ||

numerical characteristics of either a sample or a population |

10 points

### QUESTION 2

Stratified random sampling is a method of selecting a sample in which

the sample is first divided into strata, and then random samples are taken from each stratum | ||

various strata are selected from the sample | ||

the population is first divided into strata, and then random samples are drawn from each stratum | ||

None of these alternatives is correct. |

10 points

### QUESTION 3

A theorem that allows us to use the normal probability distribution to approximate the sampling distribution of sample means and sample proportions whenever the sample size is large is known as the

approximation theorem | ||

normal probability theorem | ||

central limit theorem | ||

central normality theorem |

10 points

### QUESTION 4

In point estimation

data from the population is used to estimate the population parameter | ||

data from the sample is used to estimate the population parameter | ||

data from the sample is used to estimate the sample statistic | ||

the mean of the population equals the mean of the sample |

10 points

### QUESTION 5

The sample statistic s is the point estimator of

μ | ||

σ | ||

x ̅ | ||

p ̅ |

10 points

### QUESTION 6

The sample mean is the point estimator of

μ | ||

σ | ||

x ̅ | ||

p ̅ |

10 points

### QUESTION 7

The standard deviation of all possible x ̅ values is called the

standard error of proportion | ||

standard error of the mean | ||

mean deviation | ||

central variation |

10 points

### QUESTION 8

A sample statistic, such as a sample mean, is known as

a statistic | ||

a parameter | ||

the mean deviation | ||

the central limit theorem |

10 points

### QUESTION 9

The purpose of statistical inference is to provide information about the

sample based upon information contained in the population | ||

population based upon information contained in the sample | ||

population based upon information contained in the population | ||

mean of the sample based upon the mean of the population |

10 points

### QUESTION 10

Random samples of size 81 are taken from an infinite population whose mean and standard deviation are 200 and 18, respectively. The distribution of the population is unknown. The mean and the standard error of the mean are

200 and 18 | ||

81 and 18 | ||

9 and 2 | ||

200 and 2 |

QUIZ 5:

### QUESTION 1

For the interval estimation of μ when σ is known and the sample is large, the proper distribution to use is

the normal distribution | ||

the t distribution with n degrees of freedom | ||

the t distribution with n + 1 degrees of freedom | ||

the t distribution with n + 2 degrees of freedom |

5 points

### QUESTION 2

An estimate of a population parameter that provides an interval of values believed to contain the value of the parameter is known as the

confidence level | ||

interval estimate | ||

parameter value | ||

population estimate |

5 points

### QUESTION 3

The value added and subtracted from a point estimate in order to develop an interval estimate of the population parameter is known as the

confidence level | ||

margin of error | ||

parameter estimate | ||

interval estimate |

5 points

### QUESTION 4

Whenever the population standard deviation is unknown and the population has a normal or near-normal distribution, which distribution is used in developing an interval estimation?

standard distribution | ||

z distribution | ||

alpha distribution | ||

t distribution |

5 points

### QUESTION 5

The z value for a 97.8% confidence interval estimation is

2.02 | ||

1.96 | ||

2.00 | ||

2.29 |

5 points

### QUESTION 6

The t value for a 95% confidence interval estimation with 24 degrees of freedom is

1.711 | ||

2.064 | ||

2.492 | ||

2.069 |

5 points

### QUESTION 7

As the sample size increases, the margin of error

increases | ||

decreases | ||

stays the same | ||

increases or decreases depending on the size of the mean |

5 points

### QUESTION 8

The ability of an interval estimate to contain the value of the population parameter is described by the

confidence level | ||

degrees of freedom | ||

precise value of the population mean μ | ||

degrees of freedom minus 1 |

5 points

### QUESTION 9

In general, higher confidence levels provide

wider confidence intervals | ||

narrower confidence intervals | ||

a smaller standard error | ||

unbiased estimates |

5 points

### QUESTION 10

An interval estimate is a range of values used to estimate

the shape of the population's distribution | ||

the sampling distribution | ||

a sample statistic | ||

a population parameter |

5 points

### QUESTION 11

As the number of degrees of freedom for a t distribution increases, the difference between the t distribution and the standard normal distribution

becomes larger | ||

becomes smaller | ||

stays the same | ||

becomes negative |

10 points

### QUESTION 12

In order to determine an interval for the mean of a population with unknown standard deviation a sample of 61 items is selected. The mean of the sample is determined to be 23. The number of degrees of freedom for reading the t value is

22 | ||

23 | ||

60 | ||

61 |

10 points

### QUESTION 13

After computing a confidence interval, the user believes the results are meaningless because the width of the interval is too large. Which one of the following is the best recommendation?

Increase the level of confidence for the interval. | ||

Decrease the sample size. | ||

Increase the sample size. | ||

Reduce the population variance. |

10 points

### QUESTION 14

A sample of 225 elements from a population with a standard deviation of 75 is selected. The sample mean is 180.The 95% confidence interval for μ is

105.0 to 225.0 | ||

175.0 to 185.0 | ||

100.0 to 200.0 | ||

170.2 to 189.8 |

10 points

### QUESTION 15

The sample size needed to provide a margin of error of 2 or less with a .95 probability when the population standard deviation equals 11 is

10 | ||

11 | ||

116 | ||

117 |

## Tutor Answer

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