STATS ch 3
Excel's __________ function can be used to compute the sample standard deviation.
STDEV.S
The correlation coefficient ranges between
-1 and + 1
If the data distribution is symmetric, the skewness is
0
The interquartile range is the difference between the
1st Q and 3rd Q
The first quartile
25th percentile
The 75th percentile is also the
3rd quartile
The standard deviation of a sample of 100 observations equals 64. The variance of the sample equals
4096
The median of a sample will always equal the
50th percentile
Which of the following is not a measure of dispersion? the range the 50th percentile the standard deviation the interquartile range
50th percentile
The empirical rule states that, for data having a bell-shaped distribution, the percentage of data values being within one standard deviation of the mean is approximately
68
The variance of a sample of 81 observations equals 64. The standard deviation of the sample equals
8
Excel's __________ function can be used to compute the sample correlation coefficient.
CORREAL.
Excel's __________ function can be used to compute the sample covariance.
COVARIANCE.S
__________ can be used to make statements about the proportion of data values that must be within a specified number of standard deviations of the mean.
Chebyshev's theorem
Excel provides functions for computing the mean median mode Excel provides functions for all of these.
Excel provides functions for all of these.
Which of the following symbols represents the size of the population? σ 2 σ μ N
N
If two groups of numbers have the same mean, then their standard deviations must also be equal medians must also be equal modes must also be equal None of the other answers are correct.
None
Excel's __________ function can be used to compute the population standard deviation. MAX MODE STDEV None of the other answers are correct.
None are correct
Excel's __________ function can be used to compute the population variance. MAX MODE VAR None of the other answers are correct.
None are correct
Since the mode is the most frequently occurring data value, it can never be larger than the mean is always larger than the median is always larger than the mean None of the other answers are correct.
None are correct
Since the population size is always larger than the sample size, then the sample statistic can never be larger than the population parameter can never be equal to the population parameter can never be zero None of the other answers are correct.
None are correct
The coefficient of variation is the same as the variance the square root of the variance the square of the standard deviation None of the other answers are correct.
None are correct
The mean of the sample is always larger than the mean of the population from which the sample was taken is always smaller than the mean of the population from which the sample was taken can never be zero None of the other answers are correct.
None are correct
Excel's __________ function can be used to compute the sample variance.
VAR.S
Positive values of covariance indicate
a positive relation between the x and the y variables
The sum of deviations of the individual data elements from their mean is
always equal to zero
The value of the sum of the squared deviations from the mean, i.e., must always be
at least zero
Excel's __________ function can be used to compute the mean.
average
In computing the pth percentile, if the index i is an integer the pth percentile is the
average of data values in position i and i + 1
A graphical summary of data that is based on a five-number summary is a
box plot
The variance of the sample
can never be negative
In computing descriptive statistics for grouped data, the ____ are used to approximate the data values in each class.
class midpoint
The mean of a sample is
computed by summing all the data values and dividing the sum by the number of items
A numerical measure of linear association between two variables is the
correlation coefficient
Since the population is always larger than the sample, the value of the sample mean
could be larger, equal to, or smaller than the true value of the population mean
The sample variance
could be smaller, equal to, or larger than the true value of the population variance
A numerical measure of linear association between two variables is the
covariance
Which of the following is not a measure of variability of a single variable?
covariance
In computing descriptive statistics from grouped data,
data values are treated as if they occur at the midpoint of a class
__________ can be used to determine the percentage of data values that must be within one, two, and three standard deviations of the mean for data having a bell-shaped distribution.
empirical rule
A box plot is a graphical representation of data that is based on
five number summary
When the data are positively skewed, the mean will usually be
greater than the median
Which of the following is a measure of dispersion? percentiles quartiles interquartile range all of these are measures of dispersion
interquartile range
If a data set has an even number of observations, the median
is the average value of the two middle items when all items are arranged in ascending order
After the data has been arranged from smallest value to largest value, the value in the middle is called the
mean
Generally, which one of the following is the least appropriate measure of central tendency for a data set that contains outliers?
mean
The coefficient of variation indicates how large the standard deviation is relative to the
mean
The measure of location that is the most likely to be influenced by extreme values in the data set is the
mean
Excel's __________ function can be used to compute the median.
median
The 50th percentile is the
median
An important measure of location for categorical data is the
mode
The most frequently occurring value of a data set is called the
mode
Excel's __________ function can be used to compute the mode.
mode. singl
During a cold winter, the temperature stayed below zero for ten days (ranging from -20 to -5). The variance of the temperatures of the ten day period
must be at least zero
Which of the following symbols represents the size of the sample? σ 2 σ N n
n
For data skewed to the left, the skewness is
negative
The numerical value of the standard deviation can never be
negative
The population variance can never be
negative
Since the median is the middle value of a data set, it must always besmaller than the modelarger than the modesmaller than the meanNone of the other answers are correct.
none are correct
smaller than the mode larger than the mode smaller than the mean None of the other answers are correct.
none are correct
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
A(n) __________ is an unusually small or unusually large data value.
outlier between -3 and 3
μ is an example of a
population parameter
A numerical measure, such as a mean, computed from a population is known as a
population partner
The difference between the largest and the smallest data values is the
range
The measure of variability easiest to compute, but seldom used as the only measure, is the
range
A numerical measure computed from a sample, such as sample mean, is known as a
sample statistics
An important numerical measure of the shape of a distribution is the
skewness
The coefficient of determination is equal to the
squared value of the correlation coefficient
The descriptive measure of dispersion that is based on the concept of a deviation about the mean is
standard deviation
The symbol σ is used to represent the
standard deviation of a population
If the variance of a data set is correctly computed with the formula using n − 1 in the denominator, which of the following is true?
the data set is a sample
In a five-number summary, which of the following is not used for data summarization?
the mean
The measure of dispersion that is influenced most by extreme values is
the range
The interquartile range is used as a measure of variability to overcome what difficulty of the range?
the range is influenced too much by extreme values
The descriptive measure that is not measured in the same units as the original data is the
variance
Which of the following descriptive statistics is not measured in the same units as the data? 35th percentile standard deviation variance interquartile range
variance
Which of the following is not a measure of location? mean median variance mode
variance
The symbol σ 2 is used to represent the
variance of a population
A mean computed in such a way that each data value is given a weight reflecting its importance is referred to as
weighted mean
Which of the following symbols represents the mean of the sample? σ 2 σ μ x-
x-
The __________ denotes the number of standard deviations xi is from the mean .
z-score
Which of the following symbols represents the mean of the population? σ 2 σ μ
μ
Which of the following symbols represents the standard deviation of the population? σ 2 σ μ
σ
Which of the following symbols represents the variance of the population? σ 2 σ μ
σ 2
