Working with data Flashcards
What are the different categories of data?
Qualitative:
-Descriptive e.g. free text comments, interview responses
Categorial:
- Ordinal e.g. BMI (1=underwight 2=nomal…)
- Nominal e.g. status (infected, not infected etc.)
Quantitive
- Discrete = counted e.g. no. of children in family
- Continuous = measured e.g. temperature, currency
What are the different types of graphs?
Pie chart:
- categorical e.g. gender
- counted quantitive
Bar chart:
- x categorical or quantitive counted
- y quantitive
Histogram:
- x continuous quantitive
- y quantitive counted
Dot plot:
- x categorical
- y continuous quantitive e.g. heart rate
Box and Whiskers:
- x categorical
- y continuous quantitive
Scatter plot:
- x continuous quantitive
- y continuous quantitive
What kind of distribution has the same mode, mean and median?
parametric or normal distribution
mean is a centre of data set
What are methods of calculating data spreads?
Variance
Standard deviation
Standard error of mean
95% confidence intervals
What is variance?
Quantifies spread of data
Calculation: average of squared differences fro mean
What is standard deviation?
Quantifies spread of normally distributed data
Calculation: square root of variance
What is standard error of mean?
How well sample mean approximates to population mean
Calculation: standard deviation divided by square root of sample size
What is the 95% confidence interval?
The range in which the true mean value might NOT be 95% of values
Calculation: standard error x 1.96 (1.96 is the z score)
What is the mean?
Add all values together and divide by number of values
What is the median?
Order all values in ascending order and chose the middle value
What is the mode?
Identify the most frequent measured value
