Observations, Data Tables, Graphing, & Variables Review Friday, August 5th, 2016

Classifying Observations Identify whether the following observations are quantitative/qualitative and objective/subjective: Quan. Qual. Obj. Subj. Chemistry is the best class in the world. The chemistry class has 28 students. Everyone agrees Miss Scott is the best chemistry teacher.

Variables The changing factors in an experiment are called the variables, and they are the first thing you must worry about when designing your experiment. - Independent variable: Factor that is changed by the scientist - Dependent variable: Factor(s) that is measured in response to the independent variable - Controlled variable(s) – also known as constants: Factor(s) that are kept the same between experimental groups

Practice Scenario A florist wants to determine if the amount of humidity in the air affects the orchid plant. She takes two cuttings and plants them in the same type of pot in the same type of soil. She waters each plant three times a week, and they are exposed to the same amount of sunlight. She keeps one plant outside in the dry Arizona air (10% humidity) and she keeps one inside a greenhouse (humidity 70%). Every week she counts the number of flowers.

Rules for Reporting Data: Data Tables Detailed Title & Include the Date Organized Data: Use a Ruler 1st column – Independent variable 2nd-millionth column – Dependent variable

Rules for Graphing Descriptive Title Use a ruler! Should be big ~ ½ page! X-axis (independent variable) with labels & units Y-axis (dependent variable) with labels & units Even increments/scale Key/legend (if you have more than one set of data) Remember TALKS – Title, Axis with Labels, Key & Scale

A graph shows information visually A graph shows information visually. The type of graph usually depends on the kind of information being disclosed.

To read a graph: Examine the title of the graph to find out what information is shown. Examine the parts to see how they relate to one another and to the whole. Examine the labels for each part of the graph and any explanatory remarks that may be given. Use the parts to determine additional amounts

Line graphs and scatterplots use one or more lines to show changes in data. Normally the horizontal axis represents periods of time or specific times and the vertical axis gives the numerical amounts.

Correlation is how the variables relate to each other. We use graphs to show trends/patterns. We read graphs and look for trends/patterns. Correlation is how the variables relate to each other. Positive: when one variable increases, so does the other Negative: As one variable increases, the other decreases. None (no correlation): There is no apparent relationship between the variables

Interpolation vs. Extrapolation Interpolation: estimation of a value between to known values Extrapolation: estimation (infer) beyond the information you know