Descriptive Stats Flashcards
1
Q
What is the mean?
A
- The value when all the scores from a data set have been added together and then divided by the number of data sets there are.
2
Q
What is the median?
A
- Calculates the middle value when the values in the data set are placed in rank order (from smallest to largest).
3
Q
What is the mode?
A
- The value that occurs most frequently.
- If there’s 2 = bi-modal
- If there’s more than 2 = mode is meaningless.
4
Q
What is the range?
A
- Difference between the highest and lowest value.
- Not useful if there’s outliers in the data.
5
Q
What is Standard Deviation?
A
- A measure of dispersion that shows the spread of scores around the mean.
- Higher SD = More spread out scores around the mean.
6
Q
How to work out SD?
A
- Calculate the mean of the data.
- Subtract the mean from each score. (deviation)
- Square the deviation
- Find total of squared deviations.
- Divide this score by the no of scores -1.
- Find the square root of answer to step 5.
7
Q
What is a frequency table?
A
- A table showing the tally and therefore frequency of certain behaviours.
8
Q
What is a bar chart?
A
- A bar chart shows the frequency of events occurring.
- The height of the bar is the frequency.
9
Q
What are scatter graphs?
A
- Graphs displaying 2 sets of data to see if there is a correlation.
10
Q
What is normal distribution?
A
- An arrangement of data that’s symmetrical and forms a bell-shaped pattern where the mean, median, and/or mode falls in the centre at the highest peak.
- Area under the normal distribution curve represents probability and the total area under the curve sums up to 1.
11
Q
What is skewed distribution?
A
- Where frequency data is not spread evenly, the data is clustered at 1 end.
12
Q
What is positively skewed distribution?
A
- Where the mean will be more than the median.
- Will have a long tail that extends to the right
13
Q
What is negatively skewed distribution?
A
- Where the median will be more than the mean.
- Has a long tail that extends to the left.
