Statistics 1 Flashcards
Class Midpoint
(UpperBound + LowerBound) / 2
Steps of Modelling a Mathematical Problem
- Observe a real world problem
- Devise a mathematical model
- Use the model to make predictions for the real world
- Experimental data is collected from the real world
- Compare predicted and observed outcomes
- Statistical tests are used to assess the model
- Mathematical model is improved and refined
Class Width
UpperBound - LowerBound
Mean
Sum of values / number of values
Combining Means
(N1X1) + (N2X1) / (N1+N2)
N1 = number of values in first sample N2 = number of values in second sample X1 = mean of first sample X2 = mean of second sample
Coding
Definition
A kind of transformation of data
Coding
General Form
y = (x-a) / b
x = original data or mean y = new data or mean
Q1
Lower Quartile
Q2
Median
Q3
Upper Quartile
Interquartile Range
Q3 - Q1
Q1
List of Data
4 pots
Q1
Data in a Table
4 pots
Q1
Data in a Grouped Table
1/4 nth value
Q2
List of Data
4 pots
Q2
Data in a Table
4 pots
OR
n+1/2 th value
Q2
Data in a Grouped Table
n/2 th value
Q3
List of Data
4 pots
Q3
Data in a Table
4 pots
Q3
Data in a Grouped Table
3/4n th value
Variance
Symbol
σ²
Standard Deviation
Symbol
σ
Variance
Equation (list of data)
Ex² / n - (Ex /n)²
The sum of x² divided by n
Minus
(The sum of x divided by n) all squared
Standard Deviation
Equation
√variance
Variance
Equation (data in a table)
Efx² / Ef - (Efx / Ef)²
The sum of frequency times x² divided by the sum of the frequencies
Minus
(The sum of frequency times x divided by the sum of the frequencies) all squared
Variance
Equation (data in a grouped table)
Efx² / Ef - (Efx / Ef)²
x the value of x is the midpoint of each class
The sum of frequency times x² divided by the sum of the frequencies
Minus
(The sum of frequency times x divided by the sum of the frequencies) all squared
Coding - Mean
±a
±a
Coding - Variance
±a
Not effected
Coding - Standard Deviation
±a
Not effected
Coding - Mean
xa
xa