Peach Pack Flashcards
What does a Ratio do?
It is a way to compare quantities
Why are Estimates very useful for psychologists?
They help the researcher understand the data in very large data sets
What are Significant Figures?
A method of finding an approximated or estimated answer to a calculation is to round of using significant figures
When is Standard Form useful?
When writing very big or very small numbers
What are Descriptive Statistics?
- Used to describe the main trends in data
- Used to summarise the raw data from research into a more meaningful form to help researchers draw conclusions from the results
What does Descriptive Statistics include?
- Measures of central tendency - mean, median, mode
- Measures of dispersion - range, standard deviation
- Graphical representations of data - bar charts, pie chart, scatter graphs, histograms and frequency distribution
What are the 3 Main Types of Central Tendency?
- Mean
- Median
- Mode
What is a Measure of Central Tendency?
The value in a group of values which is the most typical for the data set
What is the Strength of the Mean?
All information in a set of data is used so it is the most powerful measure of central tendency and is likely to be representative of the data
What is are the Weaknesses of the Mean?
- It is sensitive, so distorted when an extreme school is present - so it is no longer representative of the set of data
- Not meaningful when used with certain types of data - mean can’t be found when data is in mutually exclusive categories
- It doesn’t reflect real-life
What is the Strength of the Median?
Not distorted by an extreme scores, so provides a more representative value for the data set
What are the Weaknesses of the Median?
- Doesn’t take account of the exact value of each item, so it’s less sensitive to the value of each piece of data
- Less meaningful with very small sets of data
- Not meaningful when used with certain types of data - e.g. data in the form of frequency counts in mutually exclusive categories
What is the Strength of the Mode?
- Most useful with data in the form of frequency counts in mutually exclusive categories - it tells us what the most frequently occurring score or category is
- Not influenced by extreme scores in skewed data
What are the Weaknesses of the Mode?
- Not useful when a set of data has many modes
- If there are only a few scores, then even small changes in the data can radically alter the mode
- Doesn’t give a proper representation of the dataset as it isn’t sensitive
What are Measures of Dispersion?
Measure of whether our scores are clustered closely around the mean or are scattered widely
How do Measures of Dispersion help us?
Help us to see whether scores are similar or very different from each other which can be useful when comparing two sets of data
What is the Strength of the Range?
•Quick and easy to calculate
What are the Weaknesses of the Range?
- Becomes less effective measure of dispersion when being used with skewed data as it is distorted by extreme scores
- Gives very little information about the spread of data
What are the different Measures of Dispersion?
- The range
* Standard deviation
What is Standard Deviation?
Gives a measure of how much on average each of the scores in the dataset deviates from the mean
What are the Strengths of Standard Deviation?
- Most sensitive + powerful measure of dispersion and is likely to be representative of the data, so shows accurately whether a set of data is tightly clustered around the mean or very spread out
- Less distorted by skewed data than the range so can be preferable
When drawing and interpreting graphs, what must you take into account?
- Axes need to be clearly labelled + the graph needs an informative title
- Care needs to be taken in the scale chosen What is Standard Deviation?
What do Tables, Graphs and Charts do?
They provide visual summaries which can show any major patterns or trends in the data
What does a Group Frequency Table Help?
- It helps to display and give an overview of the data
* The smaller the group width, the more accurate the analysis will be