Wk 1: Ch. 3: Describing Data Visually

Select all that apply: Sorting data is helpful because we can easily determine center and variability, even with large data sets. we can determine shape of the data set, even with large data sets. we can see the frequency of each data value. we can see the range of values.

- we can see the frequency of each data value. - we can see the range of values

Select all that apply: Stem-and-leaf displays can be used to analyze qualitative data. determine central tendency and dispersion. observe individual data points. analyze the small samples of integer data.

-Analyze the small samples of integer data. -Observe individual data points. -Determine central tendency and dispersion.

An ogive is useful for comparing shapes of known distributions. identifying individual data values. finding percentiles. constructing histograms.

-Finding percentiles. -Comparing shapes of known distributions.

Select all that apply: Dot plots can show which features of a data set? Variability Data entry errors Center Shape

-Variability. -Shape. -Center

Select all that apply: Histograms can be used to observe individual data points. determine the shape of the data. observe the spread or the variability of the data. construct a pie chart.

-determine the shape of the data. -observe the spread or the variability of the data

Assume that a professor gave an exam to a class of 50 students. The high score was 98 points and the low score was 53 points. The professor wants to create a frequency distribution that is divided into five bins for the exam scores. The approximate bin width for the data __________ is points but you might round up the bin width to ____________ for an easier interpretation.

9 , 10.

Cumulative frequency distributions show the the number total number of observations in the bin and any bins with limits greater. accumulated counts up to and including the current bin as the bin limits increase. the number of observations in the each bin only. total count minus the current bin count.

Accumulated counts up to, and including, the current bin as the bin limits increase.

Select all that apply: When constructing bins for a frequency distribution of quantitative data, which of the following principles should generally be followed? Bins should have equal interval widths. The bin limits should not overlap. The lower limit is excluded from the bin and the upper limit is included in MegaStat and Minitab. The last value of a class should also be the first value of the subsequent class.

Bins should have equal interval widths. The bin limits should not overlap.

A dot plot displays individual values of qualitative data. True false question.

False

A ________ ___________ is a line graph that connects the midpoints of the histogram bin intervals plus extra intervals at the beginning and end so that the line will touch the X-axis.

Frequency. Polygon

Which type of data cannot be sorted? Ratio Ordinal Nominal Interval

Nominal

An _________ is a line graph of the cumulative frequencies that is useful for finding percentiles or in comparing the shape of the sample with a known benchmark.

Ogive

When constructing a histogram what values/labels go on the horizontal (x) axis and the vertical (y) axis. Quantitative bin limits on the horizontal axis; frequency or relative frequency on the vertical axis. Histograms do not have vertical or horizontal axes. Qualitative categories on the horizontal axis; frequency or relative frequency on the vertical axis. Frequency or relative frequency on the horizontal axis; quantitative class limits on the vertical axis.

Quantitative bin limits on the horizontal axis; frequency or relative frequency on the vertical axis.

When a researcher wants to know the proportion of all observations that fall within a particular bin they would need the cumulative relative frequency distribution. frequency distribution. cumulative frequency distribution. relative frequency distribution.

Relative frequency distribution

If the data were collected from a random sample we must allow for __________ error.

Sampling

Select all that apply: Before calculating summary statistics or graphing a data set it is a good idea to Sort the data if possible. Determine if the data is time-series or cross-sectional. Visualize how data was collected. Discard any data values that you feel are unimportant.

Sort the data if possible. Determine if the data is time-series or cross-sectional. Visualize how data was collected.

Match the term with the histogram description. Symmetric: Right Skewed: Left Skewed: (A histogram with a left tail that is longer than the right tail). (A histogram with evenly distributed tails). (A histogram with a right tail that is longer than the left tail).

Symmetric= A histogram with evenly distributed tails· Right skewed= A histogram with a right tail that is longer than the left tail· Left skewed= A histogram with a left tail that is longer than a right tail

When determining the approximate width of the bins for a frequency distribution of quantitative data, the difference of what two values is divided by the number of bins? The maximum value and minimum value. The middle value and the minimum value. The maximum value and the middle value. The value of the 75th percentile and the 25th percentile.

The maximum value and minimum value.

Price Barrel/ First Quarter 2011 Select all that apply: Identify the problems with the pictured graph. There is no problem. The price of oil cannot be graphed against time. The time range needs to be specified. The vertical axis limit is too high.

The time range needs to be specified. The vertical axis limit is too high.

Select all that apply: A stem-and-leaf plot is basically: a frequency tally. a tool which uses the digits in each number to create stems and leaves. used for large samples of continuous data. a tool used in exploratory data analysis.

a frequency tally. a tool which uses the digits in each number to create stems and leaves. a tool used in exploratory data analysis.

Relative frequencies are calculated as the: a) absolute frequency for a bin divided by the total number of data values. b) product of absolute frequency for a bin and the total number of data values. c) total number of actual observations that occur below the upper limit of a particular bin. d) total proportion of observations that occur below the upper limit of a particular bin.

absolute frequency for a bin divided by the total number of data values.

Relative frequencies are calculated as the: a) total number of actual observations that occur below the upper limit of a particular bin. b) absolute frequency for a bin divided by the total number of data values. c) product of absolute frequency for a bin and the total number of data values. d) total proportion of observations that occur below the upper limit of a particular bin.

absolute frequency for a bin divided by the total number of data values.

Select all that apply: An outlier is defined as an extreme value that is located in the tail of the histogram. an extreme value that might have arisen from a different cause. an extreme value that was added to the data to confuse the analyst. an extreme value that might have arisen from measurement error.

an extreme value that is located in the tail of the histogram. an extreme value that might have arisen from a different cause. an extreme value that might have arisen from measurement error.

One of the primary goals of constructing a frequency distribution for quantitative data is to summarize the data so that there are always 7 classes or bins of data. in a manner so that each class or bin has the same number of data points. by showing frequency of values that lie within a class or bin. ensuring that the classes or bins are always of different widths.

by showing frequency of values that lie within a class or bin.

Select all that apply The vertical (y axis) for an ogive can be labeled as cumulative frequency. relative frequency. frequency. relative cumulative frequency.

cumulative frequency. relative cumulative frequency.

Once a graph is created in Excel, it cannot be modified.

false

Based on the pictured histogram the distribution of the data can best be described as positively skewed, or skewed right. negatively skewed, or skewed left. symmetrical. uniform.

positively skewed, or skewed right.

Select all that apply: The rectangles of a histogram represent the class width and frequency, or relative frequency, of the respective class represent grouped data will usually vary horizontally (width), but not vertically (height) are drawn with no space, or gaps, between them, except when there is no data in a particular bin.

represent the class width and frequency, or relative frequency, of the respective class. represent grouped data. are drawn with no space, or gaps, between them, except when there is no data in a particular bin.