Week 9 Flashcards
(44 cards)
What is biostatistics
The science of analyzing data and interpreting the results so that they can be applied to solving problems related to biology, health or related fields
What is univariate analysis
Describe one variable in a data set using a simplele statistics like counts, proportions and averages
What is multivariable analysis
Encompasses statistical tests such as multiple regression models that examine the relationships among three or more variables
( Confounding)
What is a variable
Any quantity that varies from one entity to another (sometime within an entity over time)
Any attribute phenomenon or event that can have different values
What are the two sub categories of variables
Quantitative and Qualitative
What are the two types of variables in quantitative studies
Discrete
Continuous
What are the two types of variables in qualitative sutides
Nominal
Ordinal
What is the normal variable
No intrinsic or logical order or value
You can assign numbers to different categories
But they do not have any other numeric properties
What is Ordinal variables
Intrinsic value but with no clear or equal differences between levels
Mild vs moderate vs severe pain
We can 5 is better than 4 etc but we cannot attribute being measured 4 is not two times larger than 2
How do we display qualitative data
Pie chart
Bar chart
Frequency table
Who created the first pie chart
Florence Nightingale
What is a numeric variable
Any positive real number depends on the nature of the variable can be expressed in decimals
Meaningful numeric scales
Age blood pressure # of friend temperature
What is continuous variables
Can take any value
Blood pressure
Temperature
Can be plotted as a line
What is discrete of variables
Can take a finite or limited number of variables
Age in year
No of drinks
Can be plotted as dot
What is the Interval variable
Interval is the difference is meaningful
No natural zero ( when you have 0 it doesn’t mean nothing)
Arbitrary zero: Interval tempertaure 0 dosen’t mean no 0
What is ratio variable
Ratio is meaningful
Zero means absence of attribute ( is natural)
Temperature in Kelvin 0 means absolute 0
Blood pressure a dead person
Age
Income
What are the three aspects of central tendency
mean, mode, median
What is the point of histogram
Gives you an idea of distribution of all data
What is a symmetric normal distribution
Mean meidan and mode are the same
This can be Bp
Weight
Height
What is negatively skewed normal distribution
Mode is on the high side
Mean is low
Marks in modules and tutorial
Means that most people are on the positive end of normal distribution and the outliers are on the other side
What is positively skewed
The mean is the higher side because you have a few people on the high side like salary where the outliers skew it to the right but most people make a low or moderate income
What is the range
The difference between the minimum and maximum
What are the quartiles
Mark three values split the data in half
Q1 is hald of the lower half
Q2 is the median
Q3 is the middle of the upper half
How do you calculate interquartile range
Q3-Q1