Module 2-3 Flashcards
What is Shifting?
Adding or subtracting a constant to every data value
What does shifting affect?
Measures of position
- Center
- Percentiles
- Max or Min
What values become changed in shifting?
Mean Median Min Q1 Q2
What does shifting not affect?
Variance
Standard Deviation
Range
What is Rescaling data?
When we multiply or divide all the data values by any constant
What changes in rescaling?
Mean Standard Deviation Median Range Min Max Q1 Q2
What is Z-score?
A measure of relative standing that measures how many standard deviations from the mean
How does Z-score standardizing change values?
Standardization does change the shape of the distribution of a variable,e
Standardization changes the center by making the mean 0
Standardizing changes the spread by making the standard deviation 1
What conditions do density curves have to satisfy?
Density curves are always on or above the horizontal axis
Total area under a density curve equals to 1
The total area under the curve above a certain interval is the proportion of all observation that fall into that range
What do Normal distributions curves look like?
They are symmetric, unimodal, and bell shaped
What is the center in Normal Distribution?
The mean
What is controls the spread in Normal distribution?
The standard deviation
How can we check to see if something follows the Normal distribution?
Q-Q Plots and Histograms
What is the Empirical Rule?
68% of observations fall within 1σ of the mean μ
95% of observations fall within 2σ of the mean μ
99.7% of observations fall within 3σ of the mean μ
