Exam 2 Review
- Pennsylvania State University - All Campuses
- Statistics 200
- Exam 2 Review
Last Modified: 2011-07-04
Related Textbooks:Mind on Statistics
*margin of error= measure of accuracy of a sample population
-the amount by which the sample proportion differs from the true population proportion is less than this quantity in at least 95% of all random samples.
usually reported in percentages (x 100)
EX: tall people and hand size
*can predict response variable using known values of explanatory variable
EX: equation between verbal SAT score and college GPA. Could use the equation to PREDICT potential GPA's of students.
*THE LINE IS USED FOR:
1. estimating the average value of y at any specified value of x
2. predicting the value of y for an individual, given that individual's x value
y=b0 + b1x
b0= y intercept
Handspan= -3 +0.35 (Height)
Handspan= -3 +0.35 (Height) **THIS means that handspan increases by .35 cm on average for each 1 in increase in height. we can estimate avg. diff in handspan bc if heights differ by 7 inches do [7 x .35= 2.45 cm] difference in handspans is approx 1 i.
"least sum of squared errors"
- the strength of the relationship is determined by the closeness of the points to a straight line
- the direction is determined by whether one variable generally increases or decreases when the other variable increases
- represented by "r"
- measures sometimes called "correlation coefficient"
- doesn't matter which variable is x and which is y
- Correlation coefficients always between -1 and +1
- a correlation of -1 or +1 indicates a perfect linear relationship and all data points fall on the same straight line
- correlation of 0 indicates that the best straight line thru data is horizontal
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