Lecture 2+3-Descriptive Statistics and Data Presentation

Question 1

what are descriptive stats

Answer 1

• first step in analysis
• organize/summarize set of measurments
• id general features and trends in a set of data
• convey info a/b a group of study subjects to an audience

Question 2

what are the four types of quantitative data [DONC]

Answer 2

1. nominal (least comlex)
2. ordinal
3. discrete
4. continuous

Question 3

Define nominal data

Answer 3

• measurements can be placed into unordered categories or classes
• numbers can rep categories but the number is just a label
• order AND magnitude are UNIMPORTANT

Question 4

Describe a type of nominal data

Answer 4

-if there are only two distinct categories the measurements are called: binary or dichotomous

Question 5

give an example of binary or dichotomous

Answer 5

mortality status: 1 dead 0 alive
diagnosis of lung cancer: 1 yes 0 no

(numbers can be switched up, 1 can mean either dead or alive)

Question 6

What are some examples of nominal data

Answer 6

• political party
• type of medial insurance
• race or ethnicity
• cause of death

Question 7

Define OR-dinal data

Answer 7

• OR-dered categories
• ORDER is meaningful
• magnitude of numerical values still unimportant
• difference between consecutive categories is not always the same

Question 8

What is an example of OR-dinal data?

Answer 8

severity of cardiac symptoms:

1. asymptomatic
2. mild symptoms
3. moderate symptoms
4. severe symptoms
   - difference between 1 and 2 is not necessarily the same difference between 4 and 5

ranks: like ordering the states in the US based on average household income in 2016

Question 9

What is the Likert scale

Answer 9

• an example or OR-dinal data

- used in many surveys: strongly agree, agree, neither agree nor disagree, disagree, strongly disagree

Question 10

What is categorical data

Answer 10

-nominal and OR-dinal measurements TOGETHER

Question 11

More about categorical data

Answer 11

• numbers used to represent categories are arbitrary (just labels, distance between them means nothing)
• most math operations (like taking average) do not make sense

Question 12

Define Discrete Data

Answer 12

• step up from categorical data
• measured quantities that take on MEANINGFUL numerical values, but are restricted to integers or counts
• BOTH the order and the magnitude of the numbers are IMPORTANT
• **differences between values mean the same thing
• numbers are not merely labels, math rules can be applied

Question 13

What are some examples of discrete data

Answer 13

• number of medication errors in a hospital over a one week period (diff b/w 1 and 2 errors is the same as 7 and 8; cant have 2.3 errors)
• number of homicides in MA in 2017
• number of cases of Zika virus reported in Miami in July 2017
• Number of times a female has given birth
• number of new cases of diabetes diagnosed in Canada over a one year period

Question 14

Define continuous data?

Answer 14

• measured quantities that are not restricted to specific numerical values
• fractional values (and decimal places) are possible-but not required