Test 1

What does the frequency polygon have an advantage over to a histogram?

It allows us to compare directly two or more frequency distributions

How do you tell positive or negative skewness in a box plot?

Longer of the whiskers

_____ can be computed for an open-ended frequency distribution if the ______ does not lie in an open-ended class.

Median

_____ is not affected by extremely large or small values and is therefore a valuable measure of central tendency when such values occur.

Median

What must you know to develop a box plot?

Minimum Quartile 1 Median Quartile 3 Maximum

The ____ is the value of the observation that appears most frequently.

Mode

_____ is a chart that shows the proportion or percent that each class represents of the total number of frequencies.

Pie charts

_____ is used for relative frequency.

Pie charts

Is bar charts used for qualitative or quantitative data?

Qualitative data

What are the measures of dispersion?

Range Mean deviation Variance and Standard Deviation

Class frequencies can be converted to ______ _____ ________ to show the fraction (which can be converted to %) of the total number of observations in each class.

Relative class frequencies

The ________ is the only measure of central tendency where the sum of the deviations of each value from the mean is zero.

arithmetic mean

What is the most widely used measure of location and requires the interval scale?

arithmetic mean

The ____ the dispersion, the ____ you certain you are.

bigger less

What does a histogram and frequency polygon have in common?

both provide quick picture of the main characteristics of the data (highs, lows, points of concentration, etc.)

Frequency polygon consists of line segments connecting the points formed by the intersections of the ______ and the ______.

class midpoints class frequencies

What is a second reason for studying the dispersion in a set of data?

compare the spread in two or more distributions

Every set of what levels of measurement have a median?

ratio-level interval-level ordinal-level

The mean is always ______ unless it gets negatively skewed.

right

For ungrouped data, the _______ is the sum of all the sample values divided by the number of sample values

sample mean

A frequency polygon also shows the _____ of a distribution and is similar to a ______.

shape histogram

The ____ is the most widely used measure of dispersion.

standard deviation

What advantage does the histogram have?

depicting each class as a rectangle, with the height of the rectangular bar representing the number in each class

How do you convert a frequency distribution to a relative frequency distribution?

each class frequency is divided by total number of observations

Frequency table is a grouping of _______ data into mutually exclusive and collectively exhaustive classes showing the number of observations in each class.

qualitative

Stem-and-leaf display condenses qualitative or quantitative information?

quantitative

_______ is a grouping of quantitative data into mutually exclusive categories showing the number of observations in each class.

Frequency distribution

What has a wide application in business and economics because we are often interested in finding the percentage changes in sales, salaries, or economic figures, such as the GDP, which compound or build on each other?

Geometric Mean

What is useful in finding the average change of percentages, ratios, indexes, or growth rates over time?

Geometric Mean

______ for a frequency distribution based on quantitative data is very similar to the bar chart showing the distribution of qualitative data.

Histogram

What are the three graphic forms of a frequency distribution?

Histograms Frequency polygons Cumulative frequency distributions

What is the rule to determine number of classes (k)?

"2 to the k rule" 2^k > n

What are the major characteristics of arithmetic mean?

-all values are used -it is unique -the sum of the deviations from the mean is 0 -It is calculated by summing the values and dividing by the number of values

The relative frequency captures the relationship between what?

-class total -total number of observations(% or fraction)

What are the four shapes commonly observed in skewness?

-symmetric -positively skewed, Mode, Median, Mean -negatively skewed, Mean, Median, Mode -bimodal

Pearson's Coefficient of Skewness

3(mean-median)/SD

Why study dispersion?

A measure of location, such as the mean or the median, only described the center of the data. It is valuable from that standpoint, but it does not tell us anything about the SPREAD of the data.

_______ is a graph in which the classes are reported on the horizontal axis and the class frequencies on the vertical axis. The class frequencies are proportional to the heights of the bars.

Bar Charts

The number of observations in each class

Class frequency

The ______ is obtained by subtracting the lower limit of a class from the lower limit of the next class

Class interval (i)

A point that divides a class into two equal parts. This is the average of the upper and lower class limits.

Class midpoint

What is used to study the relationship between two variables when one or both are nominal or ordinal scale?

Contingency table

________ is a table used to classify observations according to two identifiable characteristics.

Contingency table

What is Step 5 for constructing a frequency table?

Count the number of items in each class

What is the first step in constructing a frequency tWhaaable?

Decide on the number of classes

Pearson's Coefficient of Skewness

Defines skewness as a multiple of the standard deviation of a set of values. Negative values signify a data set with greater weight given to values below the median while positive values signify the opposite.

Frequency tables uses _____ statistics.

Descriptive

What is step 2 in constructing a frequency table?

Determine the class interval or width

_____ groups the data as little as possible and the identity of an individual observation is not lost

Dot plot

One graphical technique we use to show the relationship between variables is called a _________

Scatter diagram

What is Step 3 for constructing a frequency table?

Set the individual class limits

The major advantage to organizing the data into frequency distribution is that we get a quick visual picture of what?

Shape of distribution

What is Step 4 for constructing a frequency table?

Tally the vehicle selling prices into the classes

What does the interquartile range describe?

The middle 50% of the observations

Besides central location (mean, median, mode) and data dispersion (range, standard deviation), what is another characteristic of a set of data?

The shape

What is the formula for determining the class interval?

i >= (H-L)/k

A scatter diagram requires that both of the variables be at least _____________.

interval scale

Every set of what levels of measurement have a mean?

interval-level ratio-level

The geometric mean will always be _____ than or equal to the arithmetic mean.

less

Alternative ways of describing spread of data include determining the ________ of values that divide a set of observations into equal parts. These measures include what?

location quartiles deciles percentiles

The _____ is affected by unusually large or small data values.

mean

A set of data has a unique ______

mean or median

mode>median>mean

negative skewness, skewed to the left

mode<median<mean

positive skewness, skewed to the right

What is the advantage of the stem-and-leaf display over a frequency distribution?

the identity of each observation is not lost

For ______ data, the population mean is the sum of all the population values divided by the total number of population values

ungrouped

Relative Dispersion

unitless and is used to compare the variability of two different distributions that have different measures or values

Weighted mean equation

x bar= E(w*x)/Ew