Scientific Method

The Scientific Method- Review Problem (Question) Background Information Observation Inference Hypothesis Experiment: Variables Collect/Analyze Data Conclusion Theory

Data Collection/Analysis The collection of data can occur in 2 forms: Qualitative or Quantitative You can collect data from 2 sources Collect/experiment yourself: Primary Data Find others data to analyze: Secondary Data

How do you make sure your data is valid and good? Data should not be contaminated by poor measurement or errors in procedure. Eliminate confounding variables from study or minimize effects on variables. (Good CONTROLLED variables) Representativeness: Does your sample represent the population you are studying? Must use random sample techniques.

What makes a good quantitative research design? 1. Freedom from Bias Bias: When observations favor some individuals in the population over others.  2. Freedom from Confounding Variables Confounding: When the effects of two or more variables cannot be separated. 3. Control of Extraneous Variables Controlled Variables: Any variable that has an effect on the dependent variable. 4. Statistical Precision to Test Hypothesis

Precise versus Accurate Accuracy: how close a measured value is to the actual (true) value. Precision: how close the measured values are to each other. So, if you are playing soccer and you always hit the left goal post instead of scoring, then you are not accurate, but you are precise! Precise but not accurate Accurate but not precise Accurate and precise

Scientific Method- Senses Lab What is the problem we are trying to answer? (Fill it in on your lab sheet) What is some background knowledge/observations we have about our senses? What inferences can we make?

Scientific Method- Senses Lab Write a hypothesis in the: If__________, then __________, because _________. What is the independent variable? What is the dependent variable? What are some controlled variables we need to think about?

Scientific Method- Senses Lab Procedure In pairs One drops ruler, one reacts Repeat each sense 5 times (5 trials), for each of the 3 senses (Sight, Touch, Sound) Record data as you go, switch once you are finished

Scientific Method- Senses Lab Catcher: Start with top of index finger at 0cm (ruler should have measurements on index finger side); fingers close to ruler but NOT touching Highest point where index finger lands is recorded on worksheet, repeat each trial 5 times IT IS OK if the catcher does NOT catch the ruler (null result)

Graphing and Reporting

Brain 6 5 1 4 2 3 Eye 8 7 Arm ruler Biggles’ guide to… ‘Catch the ruler!’ Associative centres 5 RULER + FALLING = What should I do ? ruler 1 4 2 visual information about falling ruler Visual centres 3 Eye 8 grasping action 7 Motor command to catch ruler distance travelled Arm

Calculating Average For each trial you are required to calculate average or mean of your trials Mean= T1+T2+T3+T4+T5 5 If you had a “dropped” ruler you add it as 30cm t = 2d X 1000 g Where: t = Reaction time (milliseconds) d = Distance ruler dropped (cm) g = Acceleration due to gravity (980 cm/sec2) X 1000 = To convert the time from seconds to milliseconds. Extension: Calculate reaction time in milliseconds

Graphing and Reporting

Bar Graph cm Drop Average

How did you do? DISTANCE – REACTION TIME CONVERSION TABLE Catch Catch Distance Reaction time Distance Reaction time (cm) (milliseconds) (cm) (milliseconds) 1 50 16 180 2 60 17 190 3 70 18 190 4 80 19 200 5 90 20 200 6 100 21 210 7 120 22 210 8 130 23 220 9 140 24 220 10 140 25 230 11 150 26 230 12 160 27 230 13 160 28 240 14 170 29 240 15 170 30 250

Think about it… After you’ve tested yourself, why not experiment further. Here’s a few suggestions, do reaction times vary: for people of different ages (children versus adults)? if you use your dominant hand versus non-dominant hand? if you are tired or alert? for men or women? depending on your mood? after an alcoholic drink?

Some Thoughts… generally the older you are the longer your reaction time (that ruler keeps hitting my foot!) as you might expect, the dominant hand has a faster reaction time. in ‘Catch the ruler’, it helps to pay attention – so being alert is a great asset. who is faster ‘men or women’? …you tell me? mood affects attention and therefore reaction times. alcohol greatly increases reaction times.

Conclusion Statement- RERUN Restate: Restate the lab experiment. Describe the assignment. (include your independent, dependent and controlled variables) Explain: Explain the purpose of the lab. What were you trying to figure out or discover? Talk briefly about the procedure you followed to complete the lab. Results: Explain your results. Confirm whether or not your hypothesis was supported by the results. (Use simple language such as, “The results supported the hypothesis,” or “The results did not support the hypothesis.”) Uncertainties: Account for uncertainties and errors. Explain, for example, if there were other circumstances beyond your control that impacted the experiment (“Controlled Variables” that weren’t controlled) New: Discuss new questions or discoveries that emerged from the experiment.