Read the summary and the most important questions on Statistics | Mcgrawhill

• 1 Introduction to statistics and describing data

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• What are statistical methods?

  Statistical methods are used to summarize, simplify or condense data, but they can also be used to help us draw conclusions based onthe data that you have collected. (An example of a statistical method is calculating the average)

• Wherefor are descriptive statistics useful?

  Descriptive statistics are useful becase they can summarize or condense data.

• What is the usefulness of inferential statistics

  Inferential statistics help generate conclusions, and they also provide a measure of the uncertainty that goes with the conclusions. Inferential statistics allow you to judge how representative the data from the sample is.

• What are the four different levels of the levels of measurement?

  1. Nominal

  Categories with no numeric scales. It is impossible to define any quatitative values and / or differences between / across categories.  (Males/females)

  2. Ordinal

  The ordinal scale is about rank ordering, wherein the numeric values are limited. (2-star, 3- star, etc.) 

  3. Interval

  The interval scale refines the measurement of quantity by indicating how much the values differ. (Temperature)

  4. Ratio

  The ratio scale indicates precisely how much of the quantity exists. (weight) 

• Which two levels levels of measurement provide more information than the other two levels of measurement?

  Interval & Ratio measurement levels provide more information than Nominal & Ordinal measurement levels.

• What are the two main things that need to be considered in order to gain a good understanding of data?

  1. Central Tendency

  2. Spread

• What are frequency distributions?

  A frequency distribution consists of a set of possible categories or score values and the number of cases of each category or score.

• What is exactly a frequency?

  A frequency is how often a particular score appears in a data-set.

• What are the two types of frequency tables that exist?

  1. Frequency tables that have individual scores (A REALLY BIG ONE)

  2. Frequency tables that with ranges of scores

• What is a frequency polygon?

  A frequency polygon is another way to display frequencies graphically. It consists of a series of straight lines that connect the points where scores and frequencies intersect. Note that the lines are straight and that the polygon is closed at both ends.