VOCAB for Test 2- 3-2 to 3-4, 10-2 & 10-3

Methods used that summarize or describe characteristics of data are called _______ statistics.

descriptive

A value at the center or middle of a data set is a(n) _____.

measure of center

Which of the following is NOT a measure of center?

-census
-mean
-median
-mode

census

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.

The measure of center that is the value that occurs with the greatest frequency is the

mode

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

Which measure of variation is very sensitive to extreme values?

Range

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.

The Range Rule of Thumb roughly estimates the standard deviation of a data set as _______.

S= RANGE/4

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

The square of the standard deviation is called the _______.

variance

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

A data value is considered ______ if its z-score is less than -2 or greater than 2.

unusual

Whenever a data value is less than the mean, ______.

the corresponding z-score is negative

Which of the following is NOT a value in the 5-number summary?

-Median
-Mean
-Minimum
-Q1

Mean

A _______ exists between two variables when the values of one variable are somehow associated with the values of the other variable.

correlation

When determining whether there is a correlation between two variables, one should be a ______ to explore the data visually.

scatter-plot

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.

The ________ measures the strength of the linear correlation between the paired quantitative x- and y-values in a sample.

linear correlation coefficient r

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

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.

The linear correlation coefficient is robust. That is, a single outlier will not affect the value of r.

Which of the following is NOT one of three common errors involving correlation?

– Correlation does not imply causality.
-The conclusion that correction implies causality.
-The use of data based on averages.
-Mistaking no linear correlation with no correlation

Correlation does not imply causality

When making predictions based on regression lines, which of the following is not listed as a consideration?

-Use the regression equation for predictions only if the graph of regression line on the scatter-plot confirms that the regression line fits the point reasonably well.
-Use the regression equation for prediction only if the linear correlation coefficient r indicates that there is a linear correlation between two variables.
-Use the regression line for prediction only if the data go far beyond the scope of the available sample data.
-If the regression equation does not appear to be useful for making predictions, the best predicted value of a variable is its point estimate.

Use the regression line for prediction only if the data go far beyond the scope of the available sample data

In a scatter-plot, a(n) _________ is a point lying far away from the other data points.

outlier