
Term
The weighted mean is used for what data? 

Definition


Term
What is the F_{j} in the weighted mean formula? 

Definition
Frequency of the specific class 


Term
What is X_{j} in the weighted mean formula? 

Definition
the midpoint/average of each class interval 


Term
How to calculate the weighted mean : 

Definition
 Find the average/midpoint for each class
 then multiply the class frequency by the class average for EACH CLASS = X_{j} * F_{j}
 Add together X_{j} * F_{j}of each class
 Divide the sum of X_{j} * F_{j} of each class by sum of the frequencys of all the classes_{}



Term
What factor determines the appropriate measure of central tendency? 

Definition
the symmetry of the data/ frequency distribution 


Term
What is a normal (symmetrical) frequency distribution? 

Definition
THe values of your data set are distributed fairly evenly on both sides of the mean of the data 


Term
Where is the mode, median, and mean located on the distribution curve? 

Definition
Center of a distribution curve 


Term
What is a skewed distribution?


Definition
The data values are distributed unevenly on both sides of the mean of the data 


Term

Definition
The greatest frequency of the data occurs toward the low end of the range
The mean of the data values is pulled away from the area of the greatest frequency toward the right (positive) direction of the xaxis by a few high values in the data set



Term

Definition
The greatest frequency of the data occurs toward the high end of the range
The mean of the data is toward the left (negative)



Term
What measures of central tendency can be used for a normal distribution?


Definition
ALL THREEmode, median, mean



Term
What measures of central tendency can be used for a skewed distribution?


Definition


Term
What measures of central tendency can be used for an extremely skewed distribution and bimodal?


Definition


Term
What do measures of dispersion and variability tell you? 

Definition
They provide an indication of the degree to which data values are distributed to either side of their mean 


Term

Definition
The difference between the largest and smallest data values 


Term
What is standard deviation? 

Definition
Based on individual deviations of each data value in a data set from their mean 


Term
Sample Standard Deviation 

Definition


Term
Population Standard Deviation 

Definition


Term
What is the coefficient of variation? 

Definition
A realtive measure (percentage) of dispersion and variability 


Term
In what circumstances should the coefficient of variation be used? 

Definition
 When comparing standard deviations between geographic regions
 When comparing the standard deviations of two or more variables with different measurement units
 when comparing the standard deviation of two or more variables whose data values are significantly different in magnitude



Term
Coefficient of Variation (sample) Formula 

Definition


Term
Coefficient of Variation (population) Formula 

Definition


Term
What does Pearson Correlation Coefficient (pearsons r) determine? 

Definition
The strength of a relationship between two variables 


Term
What does the "t test" determine? 

Definition
If Pearson's R is statistically significant
if we can rely on pearsons r



Term
Pearsons R
Correlation Coefficient Formula 

Definition


Term

Definition
One degree of freedom is subtracted for each variable



Term
How to test for statistical significance: 

Definition
 Calculate pearsons r
 Calculate ttest
 Use ttest and degrees of freedom to find the critical value
 Compare the ttest to the critical value: must be equal to or greater than the critical value



Term

Definition


Term
Coefficient of Determination Formula 

Definition
coefficient of determination = r^{2} * 100 


Term

Definition


Term

Definition

