What is Statistics? (Exam 1)

Question 1

group

Answer 1

usually referred to as a population/population of interest

Question 2

question

Answer 2

usually asks to describe the distribution of a variable across the population

Question 3

variable

Answer 3

a characteristic recorded about individuals in the population

Question 4

distribution

Answer 4

a model that explains all possible values of the variable and the likelihood of observing each value

Question 5

why might we may not be possible to measure our variable across all individuals in the population?

Answer 5

resource constraints:
- cost of contacting an entire population
- time required to contact an entire population
- difficulty contacting/getting responses from all individuals in a population

Question 6

sample

Answer 6

look at a subset of the population, rather than the whole thing, should be representative of the population

Question 7

representative

Answer 7

sample should be a mirror image of the population (all individuals in the population are just as likely to be included and no groups are systematically excluded… equally likely to be selected)

Question 8

unweighted sample

Answer 8

the distribution of each of the variables within our SAMPLE

Question 9

weighted sample

Answer 9

the distribution of each of these variables in our POPULATION

Question 10

statistics

Answer 10

• science of collecting, organizing, interpreting numerical facts (“data”)
• using data and knowledge about randomness to condense, communicate, contextualize info
• provide insight into the setting from which the data came
• allows us to generalize what we see in our sample to what we would expect to see had we studied the complete population

Question 11

outline of a statistical analysis

Answer 11

1) identify the population of interest & the question about population
2) collect date (sampling)
3) perform preliminary data analysis to explore trends that exist within the sample
4) draw conclusions about the population based on what we observed in the sample

Question 12

categorical variables

Answer 12

• assign individuals in the population into one of the several groups or categories with a common characteristic
• any variables where the data represent GROUPS
• ex: gender, hometown, zipcode

Question 13

quantitative variables

Answer 13

• numerical values for which arithmetic operations makes sense
• any variables where the data represent AMOUNTS

Question 14

discrete quantitative variables

Answer 14

• have a finite or countably infinite number of outcomes
• ex: number of employees at a business
• positive, full number

Question 15

continuous quantitative variables

Answer 15

• have an uncountably infinite number of outcomes (a large range/interval of possible outcomes)
• no pattern to list off
• ex: the daily % change in a business’ stock value
• possible outcomes: [-100, ∞)