Math 130- Exam 2

Data Science

QuaLITative

Data NOT represented by numbers

Ex. letters and Photographs

QuanTITative

Data represented by numbers

Ex. age, IQ, and weight

Relative Measure

• Quantitative

• Data that tells us something in relation to something else

• Ex. number of students per class

Absolute Meausre

• Quantitative

• Data that shows an actual value without comparing to another measure

• Ex. the total population of Binghamton

Percent Point Change  

• absolute 

• new % - old %

Percent Change

• relative

• (new - old) / old x 100%

Bar Graphs

Highlights the size difference in the data

Pie Charts 

For fractions/ percentages of a whole 

Line Graphs 

Trends over time 

Scatter Plots

Showing relation/correlation between two variables

Postive Correlation

• Both increasing

• Ex. the temperature vs. ice cream scales

• Ex. hours worked vs. income

Negative Correlation 

• When one variable is increasing the other is decreasing

• Ex. a car’s age vs. the value of the car

• Ex. outdoor temperature vs. heating cost

No correlation

• There is no relation between the two variables (they are spread apart on the graph)

• Ex. Insta followers vs. movies watched

• Ex. favorite color vs. shoe size

Mean

(the average) is the sum of all our values divided by the number of data points

Median

the middle value of our data set (halfway between the two middle values, if we collected an even number of data points) 

Mode

The value that appears in our collected data most often 

Percentile Sentence 

If you are in the “ n“ th percentile, that means you are the same or above “n” % of the data points and below ( 100 % - “n” % ) of the data points 

Features of a Misleading Graph

• manipulation of the x and/or y axis

• disproportionate sizing

• going against convention

• using the wrong data graphs

• Truncated (shortened) axis

What is an Algorithm

A step-by-step process for taking some kind of input data and producing an output.

Equation for the Probability of an event NOT occurring

P(not event) = 1 - P(event)

Which measures of center are affected by outliers in the data

The mean

If you are in the 99th % percentile of income for your age group, explain what that means. 

You make more than (or the same amount as) 99% percent of the other people in your age group and less than 1% of the other people in your age group.