IEE 380 Exam 2 Questions with Correct Answers Latest Update 2025-2026
The sample mean is analogous to the center of mass in mechanics. - Answers True
The units associated with the sample standard deviation are the squared measurement units of
the original sample. - Answers False
If the sample variance is calculated from a sample of n observations, then it has n - 1 degrees of
freedom. - Answers True
The median of a sample is the most frequently occurring value in the sample. - Answers False
Discrete random variables take on values across a continuum. - Answers False
The binomial distribution arises from a series of Bernoulli trials. - Answers True
The Poisson distribution is widely used as a model of the number of events in an interval. -
Answers True
The probability mass function of a discrete random variable is a description of the probabilities
associated with each possible value of the random variable. - Answers True
The sum of all of the probabilities in a probability mass function equals unity. - Answers True
The cumulative distribution function, F(x), of a discrete random variable is the sum of all of the
probabilities that are less than or equal to x, where x is a specific value of the discrete random
variable, X. - Answers True
The probability distribution of a statistic is called a sampling distribution. - Answers True
A statistic is a function of observations. - Answers True
All of the observations in a random sample are independent. - Answers True
'The central limit theorem states that the distribution of the mean of independent, identically
distributed random variables with finite variance is the normal distribution. - Answers True
A point estimator of an unknown parameter is unbiased if the expected value of the estimator
equals the parameter. - Answers True
For a fixed value of the standard deviation and a fixed sample size, a confidence interval on the
population mean will get longer as the level of confidence increases from 96% to 99%. -
Answers True
For a fixed value of the standard deviation, a 95% confidence interval on the population mean
will get shorter if the sample size increases. - Answers True
This is a correct statement of a statistical hypothesis:
The sample mean is analogous to the center of mass in mechanics. - Answers True
The units associated with the sample standard deviation are the squared measurement units of
the original sample. - Answers False
If the sample variance is calculated from a sample of n observations, then it has n - 1 degrees of
freedom. - Answers True
The median of a sample is the most frequently occurring value in the sample. - Answers False
Discrete random variables take on values across a continuum. - Answers False
The binomial distribution arises from a series of Bernoulli trials. - Answers True
The Poisson distribution is widely used as a model of the number of events in an interval. -
Answers True
The probability mass function of a discrete random variable is a description of the probabilities
associated with each possible value of the random variable. - Answers True
The sum of all of the probabilities in a probability mass function equals unity. - Answers True
The cumulative distribution function, F(x), of a discrete random variable is the sum of all of the
probabilities that are less than or equal to x, where x is a specific value of the discrete random
variable, X. - Answers True
The probability distribution of a statistic is called a sampling distribution. - Answers True
A statistic is a function of observations. - Answers True
All of the observations in a random sample are independent. - Answers True
'The central limit theorem states that the distribution of the mean of independent, identically
distributed random variables with finite variance is the normal distribution. - Answers True
A point estimator of an unknown parameter is unbiased if the expected value of the estimator
equals the parameter. - Answers True
For a fixed value of the standard deviation and a fixed sample size, a confidence interval on the
population mean will get longer as the level of confidence increases from 96% to 99%. -
Answers True
For a fixed value of the standard deviation, a 95% confidence interval on the population mean
will get shorter if the sample size increases. - Answers True
This is a correct statement of a statistical hypothesis:
