Complete Short Stats Quizzes

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COMPLETE EACH QUIZ ON SEPARATE WORD DOCUMENT

CHOOSE THE CORRECT MULTIPLE CHOICE ANSWER

QUIZ 3:

QUESTION 1

1.

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

 descriptive statistic probability function variance random variable

5 points

QUESTION 2

1.

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

1.

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

1.

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

1.

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

1.

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

1.

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

1.

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

1.

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

1.

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

1.

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

1.

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

1.

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

1.

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 0.419 0.5222 0.919

10 points

QUESTION 15

1.

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

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

1.

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

1.

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

1.

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

1.

The sample statistic s is the point estimator of

 μ σ x ̅ p ̅

10 points

QUESTION 6

1.

The sample mean is the point estimator of

 μ σ x ̅ p ̅

10 points

QUESTION 7

1.

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

1.

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

1.

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

1.

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

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

1.

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

1.

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

1.

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

1.

The z value for a 97.8% confidence interval estimation is

 2.02 1.96 2 2.29

5 points

QUESTION 6

1.

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

1.

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

1.

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

1.

In general, higher confidence levels provide

 wider confidence intervals narrower confidence intervals a smaller standard error unbiased estimates

5 points

QUESTION 10

1.

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

1.

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

1.

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

1.

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

1.

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

1.

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

Robertmariasi
School: Carnegie Mellon University

Hello there,I just wanted to tell you that I finished answering the questions given. In total there were 3 quizzes in ...

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Anonymous
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