# AP Stats: Chapter 2&3

1. what is the equation to find a z-score?
z = x-mean / standard deviation
2. how do you find a density curve? Which two questions do you need to ask yourself?
• 1.) is it above an x-axis?
• 2.) needs an area of one!
3. What is the empirical rule?
68-95-99.7
4. what does the distribution have to be so that you can use the empirical rule?
has to be a Normal Distribution.
5. ###### Splitting it from the middle, and going outwards... what do the percentages need to be for the 68-95-99.7?
• 34%
• 13.5 %
• 2.35%
• .15%
6. what are two variables that you need to analyze a scatter plot?
which one is the x and y?
explanatory and response variable
7. how do you describe a scatter plot?
S.O.F.A
8. what's S.O.F.A?
• -Strength
• -Outlier
• -Form
• -Association
9. what are the three strenghts?
• -strong linear relationship
• -mediately strong linear
• -weak linear
10. what are the types of form?
curve, linear, cluster
11. what are the types of associations?
possitive, negative and none
12. how do you find the strenght by value?
correlation coefficient
13. what's the purpose of "r"
measure the association & strenght of linear relationship
14. what happens if r= 0
it's a cluster
15. can r's resist outliers?
NO!
Author
bananavocado
ID
168203
Card Set
AP Stats: Chapter 2&3
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AP Stats: Chapter 2&3
Updated