Probability and Statistics

• How do we find the mode

  Most common piece of data
• How do we find the mean

  Sum of data / total frequency
• How do we find the median

  Order the data and find the middle value
• How do we find the range

  Highest value - lowest value
• How do we plot frequency polygons?

  Plot at the mid point and join with straight lines
• What do we always do when estimating from a scatter graph?

  Draw a line of best fit
• What does (A) mean in set notation?

  All elements *in A*

  
• What does (A’) mean in set notation?

  All elements *not in A*

  
• What does (A ∪ B) mean in set notation?

  All the elements *in A or B or both*

  
• What does (A ∩ B) mean in set notation?

  All the elements *in both A and B*

  
• How are histograms always plotted?

  Always against frequency density
• Which bound do we always plot in cumulative frequency?

  Upper bound
• Why are box plots used?

  To compare datasets
• How do we express quantities that have had items added?

  Add x … e.g. red : green = 3 : 4 becomes 3x : 4x so the probability of red will then be 3x/7x