QMB 3200 Final Exam | Complete Solutions (Answered)

QMB 3200 Final Exam | Complete Solutions (Answered) Dataset all the data collected for a particular analysis Data The facts & figures collected, analyzed, and summarized for presentation and interpretation. Element The entity on which data is collected. Variable a characteristic of interest of an element. Observation The variables associated with an individual element. Categorical Data Use numeric or ordinal values of measurement of categories. Quantitative Data use numeric (quantitative) measures Cross-sectional Data data collected at a similar point in time. Time Series data collected over several time periods. Panel Data combination of cross-sectional and time series data. Descriptive Statistics Describes data or variables Population Is the set of all data/variables of a statistical analysis. Sample is a subset of the population Statistical Inference: Uses data from a sample to make estimates and test hypothesis about the characteristics of a population. What does row 1 usually contain in Excel? Typically contains the variable's names. What does Column A usually contain in Excel? contains the elements; and the rest of the worksheet contains the data in the dataset. How do you calculate the mean in excel? =Average How do you calculate the median in excel? =median What is data analytics? the scientific process of transforming data for decision making. There are three broad areas of data analytics. Descriptive Analytics describe what has happened in the past. Predictive Analytics uses statistical models from past data to predict the future [forecasting] or access the impact of one variable on another [inference]. Prescriptive Analytics uses models seeking to find a best (optimal) solution. Often these are sometype of optimization model. The difference between data and big data are We will use data (not big data) 1. Volume - the number of observations. 2. Velocity - the speed at which data is collected. 3. Variety - the forms of data are of different types. 4. Veracity - the reliability of the data generated. Data Mining Focuses on extracting predictive information from big data. Frequency Distribution a tabular summary of data showing the number (i.e. frequency) of observations in each of several non over-lapping categories. Relative Frequency frequency of a class/ n of a class Percent Frequency relative frequency x 100 Bar Chart: a visual display of frequency; relative frequency & percent frequency distributions. How would you make a frequency table in excel? a. Select any cell in Column A b. Click Insert on the Ribbon Tab c. In Tables, click Recommend Pivot Tables d. Click OK. Pie chart a visual display of frequency; relative frequency & percent frequency distributions. How would you create a bar chart in excel? a. Select any cell from A1 to A51. b. Click the Insert tab from the Ribbon. c. In Charts, click Recommended Charts d. Click OK. [bar chart appears in a new worksheet] What are the basic steps to using excel? Access the data, Functions & formulas, Apply tools, Editing options A frequency distribution with quantitative data must define the classes for a frequency distribution by: a. determine the number of non over-lapping classes; b. determine the width of each class; c. determine the class limits. Number of Classes Typically, between 5 and 20. Small datasets have less; larger datasets have more. Width of the Class Generally, it should be the same for each class. Approximate class width = (largest data value - smallest data value)/number of classes. Class Limits Each data observation must only belong to one class. Relative Frequency Distributions frequency of the class/n To construct a frequency distribution in excel we must group the rows. What if a class has no data? [Excel automatically removes these classes] To change this: Click the Layout and Print tab Choose show items with no data; click OK Histogram A visual display of a frequency, relative frequency, or percent frequency distribution, where the variable of interest is on the horizontal axis and the frequency, relative frequency, or percent frequency is on the vertical axis. A histogram shows shows the shape of the distribution of the variable of interest. A distribution is skewed if more of the data is either to the left or right of the distribution. How would we construct a histogram in excel? a. Select any cell in the pivot table report (A3:B9) b. Click Insert on the Ribbon. c. In the Charts group, click Recommended Charts d. Click OK. set the gap width to 0 Cumulative Distributions Presents the number of data items with values less than or equal to the upper-class limit for each class Cumulative relative frequency distribution A cumulative relative frequency distribution shows the proportion of data items with values less than or equal to the upper limit of each class. Cumulative percent frequency distribution A cumulative percent frequency distribution shows the percentage of data items with values less than or equal to the upper limit of each class. Crosstabulation: a tabular summary of data for two variables (either categorical or quantitative) EX: Suppose we have data from a sample of 300 restaurants on overall quality and the meal price. (This allows us to see if there is a pattern the two variables). Scatter Diagram & Trendline: a scatter diagram is a graphical display of the relationship between two quantitative variables and a trendline provides an approximation (i.e. an estimate) of the relationship; which can be positive, negative or none. How would you create a scatter diagram in excel? a. Select cells B1:C11. b. Click Insert on the Ribbon. c. In the Charts group, click Insert Scatter (X,Y) or Bubble chart (or Recommended Chart) d. When the list of scatter subtypes appears, click scatter. e. In chart elements- Select the checkbox for Trendline. Side-by-Side & Stacked Bar Charts These are extensions of a basic bar chart as they are used to display and compare two variables. stacked bar chart A stacked bar chart has one bar broken into segments of a different color showing the relative frequency of each class. Side by side bar chart A side-by-side bar chart depicts multiple bar charts on the same display. How would we construct a side by side bar chart in excel? c. In the Charts group, click recommended charts (preview) d. Click OK Mean (or average): is the average value for a variable and the sample mean is denoted as ̅