57 terms

# IS 310

Chapters 3-5
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What measures central location for data
Mean, median mode
When computing the mean of a set of values, the sum of the values
Can be any value
In computing the mean of a sample, the value of the sum is divided by
n
A numerical value used as a summary measure for a sample, such as sample mean, is known as a
sample statistic
Since the population size is always larger than the sample size, then the sample statistic
can be smaller, larger, or equal to the population parameter.
The greek symbol, μ is an example of a
population parameter
The mean of a sample
is computed by summing all the data values and dividing the sum by the number of items
The median of a sample will always equal
the 50th percentile
The median is a measure of
central location
The 50th percentile is
the median
The 75th percentile is referred to as the
third quartile.
The pth percentile is a value that at least p percent of the observations are
less than or equal to this value
The difference between the largest and the smallest data values is the
range
The first quartile
is the same as the 25th percentile
In computing the hinges for data with an odd number of items, the median position is included
both in the computation of the lower and upper hinges.
What are the measures of dispersion?
Variance, range, interquartile range, and standard deviation
The interquartile range is
the difference between the third quartile and the first quartile.
When the data are skewed to the right, the measure of skewness will be
positive.
When data are positively skewed, the mean will usually be
greater than the median.
The interquartile range is used as a measure of variability to overcome what difficulty of the range?
The range is influenced too much by extremes.
If the variance of a data set is correctly computed with the formula using n-1 in the denominator, what is true?
The data set is a sample.
In computing descriptive statistics from grouped data,
data values are treated as if they occur at the midpoint of a class
The measure of dispersion that is influenced by extreme values is
the range
When should measures of location and dispersion be computed from grouped data rather than from individual data values?
Only when individual data values are unavailable
The descriptive measure of dispersion that is based on the concept of a deviation about the mean is?
The standard deviation
The measure of location which is the most likely to be influenced by extreme values is the data set is the?
Mean
The numerical value of the standard deviation can never be
Negative.
The counting rule that is used for counting the number of experimental outcomes when n objects are selected from a set of N objects were order of selection is not important is called?
Combination
The counting rule that is used for counting the number of experimental outcomes when n objects are selected from a set of N objects were order of selection is important is called?
Permutation
Each individual outcome of an experiment is called
a sample point
The collection of all possible sample points is an experiment is
the sample space
The graphical method of representing the sample points of an experiment is
a tree diagram
In statistical experiments, each time the experiment is repeated
a different outcome may occur.
When the assumption of equally likely outcomes is used to assign probability values, the method used to assign probabilities is referred to as the
classical method
The range of probability is
zero to one
Two events, A and B, are mutually exclusive and each have a nonzero probability. If event A is known to occur, the probability of the occurrence of even B is
zero.
The addition law is potentially helpful when we are interested in computing the probability of
the union of two events
The multiplication law is potentially helpful when we are interested in computing the probability of
the intersection of two events.
If two events are mutually exclusive, then their intersection
will be equal to zero
The union of events A and B is the even containing
all the sample points belonging to A or B, or both
If a penny is tossed three times and comes up heads all three times, the probability of heads on the fourth trial is
one-half
Which of the following is a required condition for a discrete probability function?
Σf(x) = 1
A measure of the average value of a random variable is called an
expected value
The standard deviation is the
positive square root of the variance
The variance is the measure of the dispersion or variability of a random variable. It is a weighted average of the
squared deviations from the mean
A weighted average of the value of a random variable, where the probability function provides weights is known as
the expected value
The weight of an object is an example of
A continuous random variable
When sampling without replacement, the probability of obtaining a certain sample is best given by a
hypergeometric distribution
In the textile industry, a manufacturer is interested in the number of blemishes or flaws occurring in each 100 feet of material. The probability distribution that has the greatest chance of applying to this situation is the
poisson distribution
The poisson probability distribution is a
discrete probability distribution
The binomial probability distribution is used with
a discrete random variable.
What are the characteristics 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 probabilities of the outcomes do not change from one trial to another.
What is a characteristic of a binomial experiment
the trials are independent.
What are the properties of a binomial experiment?
The experiment consists of a sequence of n identical trials, each outcome can be referred to as a success or failure, the trials are independent.
When dealing with the number of occurrences of an event over a specified interval of time or space, the appropriate probability distribution is a
poisson distribution
The key difference between the binomial and hypergeometric distribution is that with the hypergeometric distribution
the probability of success changes from trial to trial
A random variable that may take on any value in an interval or collection of intervals is known as
A continuous random variable.