Introduction to Experimental Design Histograms, Variables, and Analysis

Bellringer Create a frequency table and Histogram using the given information. Write down the frequency table and draw the histogram on your paper. Test scores for a high school Biology Test Range  Frequency 60 - 69   70 – 79 80 - 89 90 - 99 81 77 63 92 97 68 72 88 78 96 85 70 66 95 80 99 58 83 93 75 89 94 76 90 87 Note: Frequency is how many fit into each number range.

What is a histogram? https://www.mathsisfun.com/data/histograms .html A histogram is a type of bar graph. But instead of making a bar for every number, you group your data into ranges. https://www.mathsisfun.com/data/histograms .html

Hypothesis Practice Make an if/then hypothesis from the following: How does the type of shoe I wear (high-heels, tennis shoes, flip flops) affect how high I can jump? How does the number of pieces of gum I chew (1, 3, 5) affect how big of a bubble I can blow? How does the amount of water you give to a plant each day (no water, 1 spoonful, 1 cup) affect how tall the plant will grow after 3 weeks?

Independent vs. Dependent Variables Independent variable – the variable varied or manipulated by the experimenter Dependent variable – the response that is measured The independent variable is the presumed cause and the dependent variable is the presumed effect.

A note on controls Control – the factors in an experiment that you keep the same Only one variable in an experiment Control Group – a group that you do not conduct the experiment on to see if your variable is effecting the results

Variables Practice #1 Students watched a cartoon either alone or with others and then rated how funny they found the cartoon to be. Independent Variable:   Dependent Variable:

Variables Practice #2 A comprehension test was given to students after they had studied textbook material either in silence or with the television turned on. Independent Variable: Dependent Variable:

Variable Practice #3 Some elementary school teachers were told that a child’s parents were college graduates, and other teachers were told that the child’s parents had not finished high school; they then rated the child’s academic potential.   Independent Variable: Dependent Variable:

Variable Practice #4 Workers at a company were assigned to one of two conditions: One group completed a stress management training program; another group of workers did not participate in the training. The number of sick days taken by these workers was examined for the two subsequent months.   Independent Variable: Dependent Variable:

Variable Practice #5 Students at a University were split into two groups and each received a different text for a philosophy course. Once group received a traditional text book, while the other received an interactive textbook on a tablet computer. After the course, the final exam marks between the two groups of students was compared. Independent Variable: Dependent Variable:

Variable Practice #6 Try and design an experiment from the following claims.  If people spend more time using social media, then they will be less able to express themselves in conversation. Experiment: ______________________________________________________________________________________________   Independent Variable: Dependent Variable:

Variable Practice #7 Claim: Drinking energy drinks makes people more aggressive. Experiment: __________________________________________________________________________ Independent Variable: Dependent Variable:

Variable Practice #8 Taking a nap in the afternoon makes people more relaxed and less irritable for the rest of the day.   Experiment: __________________________________________________________________________________   Independent Variable: Dependent Variable:

Variable Practice #9 Spending time with a cat or dog decreases the amount of stress someone is feeling and allows them to perform better on tests. Experiment: ____________________________________________________________________________________________   Independent Variable: Dependent Variable:

Variable Practice #10 Eating breakfast in the morning increases the ability to learn in school. Experiment: ___________________________________________________________________________ Independent Variable: Dependent Variable: