Week 2 - Presenting Categorical and Numerical data

Question 1

Midterm question

How can we represent categorical data?

Answer 1

By tabulating data (for example, summary table) and by graphing data (bar charts, pie charts and pareto diagram).

Question 2

Midterm question

Describe the Pareto chart and why it is useful.

Answer 2

A special type of bar chart that presents the amounts, counts or percentages of each category in descending order left to right and also contains a a lines that represents cumulative percentage.

When you have many categories, a Pareto chart enables you to focus on the most important categories by visually separating the “vital few” from the “trivial many” categories.

Question 3

Midterm question

How do we represent numerical data?

Answer 3

We can represent it in ordered array (stem-and-leaf display) or with frequency distributions and cumulative distributions (histogram, polygon, etc).

Question 4

What are 4 frequentyly used measures of variation?

Answer 4

Range, variance, standard deviation and the z score.

Question 5

What is the range?

Answer 5

The difference between the largest and smallest data values in a set of data values.

Question 6

What are variance and standard deviation?

Answer 6

Two measures that tell you how a set of data values fluctuate around the mean of
the variable. The standard deviation is the positive square root of the variance.

Question 7

What is the Standard (Z) score?

Answer 7

The number that is the difference between a data value and the mean of the
variable, divided by the standard deviation.Z scores help you determine whether a
data value is an extreme value, or outlier—that is, far from the mean.