STATISTICS FOR E&BE | Summary (RUG)
All for this textbook (1)
Written for
Erasmus Universiteit Rotterdam (EUR)
Economie en Bedrijfseconomie
Toegepaste Statistiek (FEB11005)
All documents for this subject (9)
Seller
Follow
deminguyen
Reviews received
Content preview
Examining distributions
Learning form data:
• Understanding simple relationships/properties of processes
• Understanding complex relationships/properties
• Proving conjectures
• Disproving conjectures (hypotheses!)
• Predicting future events
• Help making decisions under uncertainty...
• Uncertainty is what we have to deal with very often.
o IMPORTANT: Statistics does not remove uncertainty
= powerful tool!
To apply statistics we need data:
- By collecting data
- Summarize data
We can distinguish two types of variables:
1. Categorical variables: places an individual in one of several groups
2. Quantitative variables: takes on numerical values for which typical arithmetic
operations make sense:
• Interval data: Difference can be meaningfully interpreted but relative
numbers not: If today’s temperature is 10 Celsius, whereas it was 5 Celsius
yesterday, we cannot say that today it is twice as warm. It is however 5
degrees warmer
• Ratio data: As interval but now also relative numbers can be interpreted.
For example: 2000 euro is twice as much as 1000 euro.
These two variables are used to determine which chart you need to use:
1. Categorical data: graphing distributions
• Pie charts
• Bar charts
o Pareto charts
2. Quantitative data: graphing distributions
• Histogram
o Horizontal axis: Classes of the quantitative variable
o Vertical axis: (Relative) frequencies of the classes
o Always numerical variables!
, o Provides a visual summary of the distribution of values.
o Looking at the plot we focus on:
• Central tendency: what is the “middle” of the observed values.
• Spread: how are the data distributed around the “middle”. In what
range of values do the observations tend to fall. Does there appear to be
high or low variability.
• Shape: Are there any striking patterns in the distribution. For example:
are there multiple peaks? Is the distribution symmetric/asymmetric?
• Stemplot
o For small data sets, a fast and slightly more detailed way to graph the
data is by means of the stemplot
• Timeplot
o = displays change over time
o Horizontal axis: Time of observation
o Vertical axis: Variable of interest
o For each observation, we have two variables:
▪ one with the time of observation
▪ other with the value of the variable of interest
, Numerical measures: central tendency
= very sensitive to observations that stand out!
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller deminguyen. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $7.17. You're not tied to anything after your purchase.