STAT EXAM 2

• raw data is the set of data in its original form.
• array is an arrangement of observations according to their magnitude, either in increasing or decreasing order.
• Advantages of Array over Raw Data - easier to detect the smallest and largest value - easier to find the measures of position
• An ungrouped set contains information on each member of a sample or population individually
• A frequency distribution for quantitative data lists all the classes and the number of values that belong to each class (grouped data)
• Class frequency – the number of observations falling in the class
• Class interval – the numbers defining the class.
• Class limits – the end numbers of the class (e.g., 50 and 55); 50 is called the lower class limit and 55 is called the upper class limit
• Class boundaries – the true class limits
• lower class boundary (LCB) is usually defined as halfway between the lower class limit of the class and the upper class limit of the preceding class
• upper class boundary (UCB) is usually defined as halfway between the upper class limit of the class and the lower class limit of the next class.
• Class size – denoted by C, is the difference between the upper and lower class boundaries of a class. It is also called the class width. It can also be computed in several ways: (1) the difference between the upper class boundaries of the class and the preceding class; (2) the difference between the lower class boundaries of the current class and the next class; (3) can also be computed by using the respective class limits instead of the class boundaries.
• Class mark (CM) – midpoint of a class interval.
• Open-end class – a class that has no lower limit or upper limit
• Sturges’ formula can be used as a first approximation.
• RF = class frequency ÷ no. of observations
• RFP = RF ∙ 100
• Cumulative Frequency Distribution (CFD) – shows the accumulated frequencies of successive classes, beginning at either end of the distribution
• Greater than CFD – shows the no. of observations greater than the LCB.
• Less than CFD – shows the no. of observations less than the UCB
• Textual Presentation - The data is incorporated into a paragraph of text.
• Advantages of Textual Presentation: (1) This presentation gives emphasis to significant figures and comparisons. (2) It is simplest and most appropriate approach when there are only a few numbers to be presented.
• Disadvantages of Textual Presentation: (1) When a large mass of quantitative data is included in a text or paragraph, the presentation becomes almost incomprehensible. (2) Paragraphs can be tiresome to read especially if the same words are repeated so many times.
• Tabular Presentation - The systematic organization of data in rows and columns
• Advantages of Tabular Presentation: (1) More concise than textual presentation. (2) Facilitates comparisons and analysis of relationship among different categories. (3) Presents data in greater detail than a graph
• Heading – consist of a table number, title, and headnote. The title is a brief statement of the nature, classification and time reference of the information presented and the area to which the statistics refer. The headnote is a statement enclosed in brackets between the table title and the top rule of the table that provides additional title information.
• Box Head – the portion of the table that contains the column heads which describe the data in each column, together with the needed classifying and qualifying spanner heads.
• Stub – the portion of the table usually comprising the first column on the left, in which the stubhead and row captions, together with the needed classifying and qualifying center head and subheads are located. The stubhead describes the stub listing as a whole in terms of the classification presented. The row caption is a descriptive title of the data on the given line.
• Field – main part of the table; contains the substance or the figures of the data.
• Source note – an exact citation of the source of data presented in the table (should always be placed when the figures are not original).
• Footnote – any statement or note inserted at the bottom of the table
• The title should be concise, written in telegraphic style, not in complete sentence
• Column labels should be precise. Stress differences rather than similarities between adjacent columns. As much as possible, two or more adjacent columns should not begin nor end with the same phrase. This is frequently a signal that a spanner head is needed.
• The arrangement of lines in the stub depends on the nature of classification, purpose of presentation or limitations of space.
• Categories should not overlap.
• The units of measure must be clearly stated.
• Show any relevant total, subtotals, percentages, etc.
• Include a source note of the data.
• Tables should be self-explanatory, although they may be accompanied by a paragraph that will provide an interpretation or direct attention to important figures.
• Remove the colors, gridlines, border and bolding