LSP 120: Quantitative Reasoning and Technological Literacy Section 118 Özlem Elgün

Making and Interpreting Graphs There are 3 types of graphs we use in Quantitative Reasoning class: 1.Pie Charts 2.Bar charts 3.XY graphs (or line graphs)

How to describe the graphs Your graph should be able to stand alone without any words to tell the reader what they are looking at. If the reader doesn't understand the graph without a caption (or story) then the graph isn't very good. In the paragraph describing the graph, you should first tell your audience briefly what the graph is about, and also point out what you want the reader to know about the graph.

Misleading Graphs Difference between a bad graph and a misleading graph Bad graph: a graph with incorrect information, incorrectly designed. Etc… Misleading graph: data is "correctly" displayed on the graph and yet gives different messages depending on how it is displayed.

Graphing Checklist and Graphing worksheet Graphing Worksheet

Percentage of… Understanding “Percentage of” in 3 ways:

IV. Deriving the formulas: Can you figure out (algebraically) why all three of these are just different versions of the same relationship? a.Starting with the formula: Derive: b.Starting with the formula: Derive:

V. Solving Problems There are two approaches to solving the following problems. The first approach is to identify the two given numbers. Then decide which version of the part/whole relationship will help you answer the question. –If you are given part and whole, then use the first version. –If you are given part and % then use the second version. –And, finally, if you are given whole and % then use the third version. The second approach is to remember the first formula, fill in the information you are given and then solve for the missing variable. For all problems, remember to use the decimal version of the %.

VI. Number Drills 2 is what percentage of 10? 2/10= 1/5= 0.2 = 20% 20% of what number is 2? 20%= 0.2 2/0.2= 10 What is 20% of 10? 20% = *10= 2

17 is 32% of what number? 17/0.32 = is what percentage of 150? 67.2/150= 0.448= 44.8% What is 233% of 71? 233%= *71= What is.7% of 50? 0.7% = *50= is 9% of what number? 35/0.09= ,003 is what percentage of 1,762,325? 10003/ = = % one million three hundred thousand is what percentage of one billion? one million three hundred thousand =1.3 million one billion= 1000 million 1.3/1000= = 0.13% one thousand is what percentage of two thousand three hundred and six? 1000/2306= = 43.37%

VII. Applications: In Chicago in the year 2000, there were approximately million African Americans, 907 thousand whites (non-Hispanic), and 754 thousand Hispanics, and 181 thousand others (other races or two or more races). What percentage of Chicagoans in 2000 were of Hispanic origin? Total: = million 0.754/2.895 = = 26%

DePaul’s undergraduate student body is approximately 21,000 students. 54% of the student body is female. Approximate how many females attend DePaul? 54% = * 21,000= 11,340

In 1993, million people in the United States were born in the United States, and the rest, 19.8 million were foreign born. What percentage of the total population of the US was foreign born? Total population = = /268.5 = = 7.37%

The sales tax is 8.75% in most counties of Illinois. If you purchase a new car for $15,000, what is the sales tax you will pay? 8.75%= *15000= $1312.5

You are in another state (not Illinois). You are buying a computer at Best Buy. The price before taxes is $949. When the cashier wrings up your purchase you owe $ What is the sales tax in this state? (You might be in Connecticut or Pennsylvania) = /949=0.06= 6%

At one point, the Tribune article refers to a subtotal of murders “with only 10% of the year yet to go.” 10% of the year is how many months? 10% = *12= 1.2 months