Lesson 18: Descriptive Statistics

Question 1

How do you make a histogram?

Answer 1

Count the number of occurrences (event occurence, ex. cups of milk per day) of a category and then plot that category versus the frequency (how often a given occurrence happened, ex. how many students drank 1 cup a day vs. how many drank 2 cups a day, etc.)

Question 2

What are the three types of histograms?

Answer 2

Normal-symmetrical in shape (also called Gaussian distributions
Skewed-Non-symmetrical shape (mean value is located closer to the tail or end of the graph)
Bimodal-Contains two distinct peaks that occur with much more frequency than other values

Question 3

Where is the mean located on a skewed distribution?

Answer 3

Towards the tail of the graph

Question 4

What is standard deviation? How is it used (generally speaking)?

Answer 4

• -The measure of variation in a data set
• -It is used to communicate the diversity of a population
• -It is used to determine relationships between different populations

Question 5

What are the steps to calculate standard deviation?

Answer 5

1–Calculate the mean
2–Subtract the mean from each data value to find the deviation
3–Square each deviation
4–Sum the results from step 3
5–Divide the sum from step 4 by n-1, where n=the number of values in the set
6-Square root the results of step 5 to obtain the standard deviation.

Question 6

What is a histogram?

Answer 6

A graphical representation of frequency distribution