Exam 1 Chapters 1 and 2 Study Guide BSAD 2130 UNO

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Statistics as a field of study
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Terms in this set (55)
Statistics as a field of study
art and science of collecting, analyzing, presenting, and interpreting data
Elements
subject, entities on which data are collected.
Variables
what you want to know, characteristic of interest for the elements.
Observations
actual data value, the set of measurements obtained for a particular element.
How elements, variables, and observations are related to each other
Total number of observations equals the number of elements multiplied by the total number of variables.
Categorical variables
Non-numerical data, numerical only if numerical doesn't make sense
Quantitative variables
numerical only
Cross-sectional study
data collected at the same or approximately the same point in time
Time series study
data collected over several time periods
Data mining definition
methods for developing useful decision making information from large databases.
Data mining purposeused to help determine what a person is most likely going to want to consume, in business.Populationthe set of all elements of interest in a particular studySamplesubset of the populationStatistical inferencelet your sample say something about the group from which they cameExperimental studyresearcher controls treatmentObservationparticipant controls treatmentCategorical scale of measurementnominal and ordinalQuantitative scale of measurementinterval and ratioNominalname, labelOrdinalorder, sequence, hierarchyIntervalevenly spaced, zero not inherentRatiocomparison of two values, zero is inherent and has to be apart of a universal meaningDescriptive statisticsall the things you collect to summarize your dataDescriptive analyticslooking at things that happened in the pastPredictive analyticslook into futureDescriptive analyticsnext steps to take based on dataBig Datavolume (large amount of data coming in), velocity (speed at which it comes in), and variety (different types of data)Ethicsdon't do anything to discredit yourself, be fair, objective, neutral, let your numbers speak for themselves.Data visualizationThe use of graphical displays to summarize and present information about a data set.Frequency distributionTabular summary of data showing the number of observations in each of several nonoverlapping categories or classes.Cumulative Frequency DistributionTabular summary of quantitative data showing the number of data values that are less than or equal to the upper class limit of each class.CrosstabulationTabular summary of data for two variables. The classes for one variable are represented by the rows; the classes for the other variable are represented by the columns.Scatter DiagramGraphical display of the relationship between two quantitative variables. One variable is shown on the horizonal axis and the other variable is shown on the vertical axis.TrendlineLine that provides an approximation of the relationship between two variables.Data DashboardSet of visual displays that organizes and presents information that is used to monitor the performance of a company of organization in a manner that is easy to read, understand, and interpret.How are relative frequency values and percent frequency values calculated?Relative frequency equals the fractions or proportion of observations belonging to a class (frequency of the class/n). Percent frequency distribution is found by taking relative frequency and multiplying it by 100.What label and details needs to be on a frequency distribution table to communicate the meaning of the data?Title, units, what it is you are observing, labels for each column.What is the sum of the frequencies of any frequency distribution? Relative frequency distribution? Percent frequency distribution?Adding all the numbers in each distribution together, for frequency distribution. Relative frequency and percent frequency should equal 1 or 100.What type of data are used to construct bar charts and pie charts?Categorial data summarized in a frequency, relative frequency, or percent frequency distribution table.Summarize the suggestions about effective pie charts on pages 36-37.Colors, shading, legends, text font, and 3D can be used to enhance the chart but it isn't necessary. In fact, it can be distracting or mess with the perspective of data. It's best to use limited color and 2d, because the simpler the better.What type of graphic displays can be constructed using quantitative data (list at least 3)?Histograms, bar graphs, pie charts.Summarize the author note regarding the number of classes and class width appropriate for a data set, pg. 42.Making them the same width reduces the chance of inappropriate interpretations by the user.What is a dot plot?Graphical device that summarizes data by the number of dots above each data value on the horizontal axis.What shapes can the distribution take when looking at a histogram?Symmetric, skewed right, skewed left.How can you determine if the data is skewed left or skewed right?If the histogram has a longer tail on the right said of the graph, it's skewed right. If the tail is longer on the left, it's skewed left.Compare and contrast frequency distribution tables and cumulative frequency distribution tables.A cumulative frequency distribution used the numbers of classes, class widths, and class limits developed for the frequency distribution. However, rather than showing the frequency of each class, the cumulative frequency distribution shows the number of data items with values less than or equal to the upper class limit of each class.Summarize the steps for creating a stem and leaf.First, arrange the leading digits of each data value to the left of a vertical line. To the right of the vertical line, we record the last digit for each data value.How is a stretched stem and leaf different from a regular stem and leaf display?Stretched stem and leaf uses two or more stems for a leading digit.Explain how a leaf unit is used on a stem and leaf display?The leaf unit indicates how to multiple the stem and leaf numbers in order to approximate the original data.When are open ended classes permitted or where are they typically found?Open end class requires only a lower class limit or an upper class limit.Compare and contrast a bar graph and a histogram.Both use lines to measure frequency. A bar graph has gaps, and the y-axis are categories. A histogram has no gaps, and the y-axis is a number range.Explain the relationships depicted by scatter diagram as presented on pg. 66.Positive relationships are when the dots trend up and to the right. Negative relationships are when the dots trends down and to the right. No apparent relationships are when the dots don't trend up or down and look like they are going straight.Why are percent frequency values more preferred when creating a stack bar graph than frequency values?The stacked bar chart is based on percentages.Where should the legend be placed on a side-by-side bar graph?To the right, or just close to the data.List the five general guidelines for increasing the likelihood your display will effectively convey the key information in the data, pg. 72.Give the display a clean and concise title. Keep the display simple. Do not use 3D when 2D is sufficient. Clearly label each axis and provide the units of measure. If color is used to distinguish categories, make sure they are distinct. If multiple colors or line types are used, use a legend to define how they are used an place the legend close to the representation of the data.