AP Statistics Chapter 2 Monica AP 1 Senior Class note
Eg: I invent a super food for my rabbit that can make her energetic and make her fur shiny. How can I prove that my food is the best food for rabbits?
Experimental unit: the single individual (person, animal, etc.) to which the different treatments are assigned. 兔子
Factor: the explanatory variable 不同的兔粮
Level: a specific value for the factor
Response variable: what you measure 毛长得好不好
Treatment: a specific experimental condition applied to the units 让兔子吃特殊兔粮
Control group: a group that is used to compare the factor against; can be a placebo 安慰剂 or the “old” or current item 吃普通兔粮
Blinding: method used so that units do not know which treatment they are getting 你不知道给你的是什么
Double blinding: neither the units nor the evaluator know which treatment a subject received 我也不知道给你的是什么 实验者随机分配
Principles of experimental design:
Control of effects of extraneous variables on the response-by comparing treatment groups to a control group (placebo or old)
Replication of the experiment on many subjects to quantify the natural variation in the experiment
Randomization: the use of chance to assign subjects to treatments
The only way to show cause & effect is with a well-designed and a well-controlled experiment!!!
Eg 2: a farm product manufacturer wants to determine of the yield of a crop is different when the soil is treated with three different types of fertilizers. Fifteen similar plots of land are planted with the same type of seed but are fertilized differently. At the end of the growing season, the mean yield from the sample plots is compared.
Experimental units: plots of land
Factors: types of fertilizer
Response variable: yield of crop
How many treatments: 3
Eg 3: a consumer group wants to test cake pans to see which works the best (bakes evenly饼是平的). It will test aluminum, glass, and plastic pans in both gas...
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