Statistics and probability

• Vacation options


  • Island beach vacation
  • Ski vacation
  • Camping
• Vacation duration


  • 1 day
  • 2 days
  • 3 days
• Sample space


  The set of all possible outcomes
• Sample space for vacation options and duration

  • 1 day island trip
  • 2 day island trip
  • 3 day island trip
  • 1 day ski trip
  • 2 day ski trip
  • 3 day ski trip
  • 1 day camping trip
  • 2 day camping trip
  • 3 day camping trip
• The sample space has 9 equally likely outcomes
• You want at least 2 days of vacation without snow

  The probability is 4/9
• Probability


  A measure of how likely an event is to happen, a number that ranges from 0 to 1
• Finding probability


  1. Step 1: Identify number of possible outcomes

  2. Step 2: Identify number of desired outcomes

  3. Step 3: Express ratio of desired to possible as fraction, decimal, or percent
• Likelihood


  The chance of an event happening, described using words
• Likelihood scale


  • Impossible
  • Unlikely
  • Equally likely
  • Likely
  • Certain
• Impossible means 0% chance, Certain means 100% chance</b>
• Mean


  The typical average, calculated by adding up all the numbers in the data set and dividing by the number of data points
• Median


  The middle number in the data set when the numbers are ordered from least to greatest
• Mode


  The number that occurs most frequently in the data set
• Finding mean, median, and mode


  1. Order numbers from least to greatest

  2. For mean, add up all numbers and divide by number of data points

  3. For median, find the middle number

  4. For mode, identify the number that occurs most frequently
• Number 1 data set

  • 120 total, 15 numbers, mean = 8, median = 8, mode = 8
• Number 2 data set


  • Mean = 83.7, Median = 81.5, Mode = 96
• Mean, median, and mode are different types of averages that represent a typical or central value for a data set
• The mean, median, and mode do not always have to be the same number