How do you calculate the mid-range?
(Highest + Lowest) / 2
What measures of central tendency are affected by outliers?
Mean
Midrange as it assumes the data is symmetrical
How do you work out the mean from a frequency table?
(Total (Frequency * X)) / Total Frequency
What values do you use when calculating the mid-range from a frequency table?
Highest and lowest X values
How do you work out the mean from a grouped frequency table?
(Total (Frequency * Midpoint of X)) / Total Frequency
How do you find the median from a cumulative frequency diagram?
Draw a line across from the middle frequency value and find where it crosses the line
How do you calculate Sxx?
Total x^2 - ((Total x)^2) / n)
What is the formula for mean squared deviation?
Sxx / n
What is the formula for root mean squared deviation?
SqRt (Sxx / n)
What is the formula for variance?
Sxx / n-1
What is the formula for standard deviation?
SqRt (Sxx/n-1)
What would you change about the formula for msd/rmsd/var/sd if you’re working from a frequency table?
Use ‘total frequency’ instead of ‘n’
How do you test for outliers?
2 Standard Deviations from the mean OR 1.5 IQR below the first quartile or above the third quartile
Does multiplication or addition affect the standard deviation?
Multiplication