COMM170 Lecture Notes - Lecture 4: Standard Deviation, Unimodality
COMM170 Lecture Notes Thursday 23rd March 2017
Couicatig the S word
Probability and Statistics
- Statistics can be used to predict the probability of what could happen in the future.
o E.g. amount of rainfall
Terminology of Probability
- Odds
- Chance
- Likelihood
- Certainty
Informal measurements
- Impossible, never
- Unlikely, not probable
- Likely, probably
- Certain, definite
Formal measurements
- More than 0
- Less than ½
- More than ½
- Less than 1
Independent events
- i.e. tossing a coin.
- Each toss in independent
- The previous toss does not affect the next toss.
Use of Chance
- Think critically when analysing
- Who published the data?
- What is the data telling us?
Distributions
- How the data is spread out over the range.
- Can be normal – data is equal on both sides of the graph
- Can be skewed – to one side of the graph
o Negatively – to the right
o Positively – to the left
The M words
Median – the middle score. The number that is directly in the middle of the data. If there is
an even number of numbers, add the two middle numbers together and divide by 2
Mode – the most popular score. If two or more numbers have the most, it is call BIMODAL
find more resources at oneclass.com
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Document Summary
Statistics can be used to predict the probability of what could happen in the future: e. g. amount of rainfall. The previous toss does not affect the next toss. How the data is spread out over the range. Can be normal data is equal on both sides of the graph. Can be skewed to one side of the graph: negatively to the right, positively to the left. The number that is directly in the middle of the data. If there is an even number of numbers, add the two middle numbers together and divide by 2. If two or more numbers have the most, it is call bimodal. Add all scores and divide by number of scores. Range take the min score from the max score. The range of a set of scores is the highest score minus the lowers score. The range of a distribution is how much deviation there is away from the mean: standard deviation.
