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Control Variables and Control Groups

Control Variables and Control Groups. Is there a difference?. Let’s say a scientist develops a special vitamin, Study No More, that claims to help students remember everything the teacher says in class which, in turn, will keep them from having to study. ( Woooohoooo ! ) IV:

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Control Variables and Control Groups

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  1. Control Variables and Control Groups Is there a difference?

  2. Let’s say a scientist develops a special vitamin, Study No More, that claims to help students remember everything the teacher says in class which, in turn, will keep them from having to study. (Woooohoooo!) IV: taking STUDY NO MORE DV: student’s memory Testable Question: Does taking STUDY NO MORE improve a student’s memory in class?

  3. How would we know if the scientist’s claim are true? What needs to happen in order to figure this out? Is this the same as a control variable? Explain.

  4. A control group is the “normal” group that IS NOT exposed to the independent variable. This group is used to compare the results to observe if the independent variable caused a change. The experimentalgroup is the group who ISexposed to the independent variable. They are the “guinea pigs” of the group.

  5. Writing Our Hypothesis… • Hypothesis statements are what you think the outcome will be (infer or predict) in the experiment based on your observations. • They are usually written in the following format: “If IV, then DV. Hypothesis: If a student takes STUDY NO MORE, then he/she will improve his/her memory.

  6. Does STUDY NO MORE really work? • 100 students took part in the experiment to test STUDY NO MORE vitamins. Here are the results: • Of the 50 students who took STUDY NO MORE, 38 could not remember everything while 12 could remember most. • Of the 50 students who did not take STUDY NO MORE, 32 could not remember everything while 17 could remember most. One student remembered everything the teacher said in class. • What conclusion can we make about STUDY NO MORE? STUDY NO MORE does not really improve a student’s memory.

  7. Got to practice to be perfect! Krusty was told that a certain itching powder was the newest best thing on the market, it even claims to cause 50% longer lasting itches. Interested in this product, he buys the itching powder and compares it to his usual product. One test subject (A) is sprinkled with the original itching powder, and another test subject (B) was sprinkled with the Experimental itching powder. Subject A reported having itches for 30 minutes. Subject B reported to have itches for 45 minutes • Control Group • Group A • Independent Variable • powder • Dependent Variable • Length of itchiness • Explain whether the data supports the advertisements claims about its product.

  8. Just a little more practice! Patrick and SpongeBob love to blow bubbles! Patrick found some Super Bubble Soap at Sail-Mart. The ads claim that Super Bubble Soap will produce bubbles that are twice as big as bubbles made with regular bubble soap. Patrick and SpongeBob made up two samples of bubble solution. One sample was made with 5 oz. of Super Bubble Soap and 5 oz. of water, while the other was made with the same amount of water and 5 oz. of regular bubble soap. Patrick and SpongeBob used their favorite bubble wands to blow 10 different bubbles and did their best to measure the diameter of each one. The results are shown in the chart on the next slide:

  9. What did the Super Bubble ad claim? • What is the independent variable? • Type of bubble solution • What is the dependent variable? • Size or diameter of bubble • What is the experimental control? • Regular soap bubble • What can you conclude from the data?

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