# VOCAB For Test 2: 3-2 To 3-4, 10-2 & 10-3

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question
Methods used that summarize or describe characteristics of data are called _______ statistics.
descriptive
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A value at the center or middle of a data set is a(n) _____.
measure of center
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Which of the following is NOT a measure of center? -census -mean -median -mode
census
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Which of the following is NOT a characteristic of the mean? -The mean is relatively reliable. -The mean is called the average by statisticians. -The mean is sensitive to outliers. -The mean takes every data value into account.
The mean is called average by statisticians.
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The measure of center that is the value that occurs with the greatest frequency is the
mode
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Which of the following is always true? -For skewed data, the mode is farther out in the longer tail than the median. -The mean and median should be used to identify the shape of the distribution. -Data skewed to the right have a longer left tail than right tail. -In a symmetric and bell-shaped distribution, the mean, median, and mode are the same.
In a symmetric and bell-shaped distribution, the mean, median, and mode are the same
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Which measure of variation is very sensitive to extreme values?
Range
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Which of the following is NOT a property of the standard deviation? -The value of the standard deviation is never negative -The standard deviation is a measure of variation of all data values from the mean. -When comparing variation in samples with different means, it is good practice to compare the two sample standard deviations. -The units of the standard deviation are the same as the unites of the original data.
When comparing variation in samples with different means, it is good practice to compare the two sample standard deviations.
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The Range Rule of Thumb roughly estimates the standard deviation of a data set as _______.
S= RANGE/4
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For data sets having a distribution that approximately bell-shaped, ______ states that about 68% of all data values fall within one standard deviation from the mean.
the Empirical Rule
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The square of the standard deviation is called the _______.
variance
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When a data is converted to a standardized scale representing the number of standard deviations the data value lies from the mean, we call the new value a ______.
z-score
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A data value is considered ______ if its z-score is less than -2 or greater than 2.
unusual
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Whenever a data value is less than the mean, ______.
the corresponding z-score is negative
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Which of the following is NOT a value in the 5-number summary? -Median -Mean -Minimum -Q1
Mean
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A _______ exists between two variables when the values of one variable are somehow associated with the values of the other variable.
correlation
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When determining whether there is a correlation between two variables, one should be a ______ to explore the data visually.
scatter-plot
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Which of the following statements about correlation is true? -We say that there is a positive correlation between x and y if there x-values increase as the corresponding y-values increase. -We say that there is a positive correlation between x and y if there is no distinct pattern in the scatter-plot. -We say that there is a negative correlation between x and y if the x-values increase as the corresponding y-values increase. -We say that there is a positive correlation between x and y if the x-values increase as the corresponding y-values decrease.
We say that there is a positive correlation between x and y if the x-values increase as the corresponding y-values increase.
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The ________ measures the strength of the linear correlation between the paired quantitative x- and y-values in a sample.
linear correlation coefficient r
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Which of the following is NOT a requirement in determining whether there is a linear correlation between two variables? -Any outliers must be removed if they are known to be errors. -If r>1, then there is a positive linear correlation. -The sample of paired data is sample random sample of quantitative data. -A scatter-plot should be visually show a straight-line pattern.
If r>1, then there is a positive linear correlation
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Which of the following is NOT a property of the linear correlation coefficient r? -The value of r is always between -1 and 1 inclusive. -The value of r is not affected by the choice of x or y. -The value of r measure the strength of a linear relationship. -The linear correlation r is robust. This is, a single outlier will not affect the value of r.