Summary
Summary Measurement Theory and Assessment Lecture Notes
- Course
- Institution
Summary of the lectures
[Show more]
Seller
Follow
jelenawilliams
Reviews received
Content preview
Measurement and DiagnosticsChapter 1
- in most cases we want to be able to tell something about a phenomena in a population
- to do so we use statistical inference which is used to draw conclusions on the population based on
a representative sample
- in statistics the term inference refers to the generalisation of observations, characteristics or traits
- a variable is a characteristic of a sampling unit, which varies between the units
• in the eating disorder research, the EDQ score is a variable and the score on the EDQ varies
from person to person
• this does not mean that two people cannot have the same EDQ score
- the distribution of a variable tells us how often a particular test score occurs or what the chance is
of a certain test score
- sometimes data is normally distributed as shown above but the shape also differs from sample to
sample
- the variance and the standard deviation give an indication of the extent to which the data is
scattered
Page 1
, - the descriptive statistics we use to describe a distribution of test scores are also called parameters
- the normal distribution has two parameters (mean score and the standard deviation)t
- parameter estimations differ between samples because every sample contains different sampling
units
- the standard error of a parameter estimation is important because it portrays how precise an
estimation is
^) = σ^/ √N
s.e.(μ
- a standard error of a parameter can be interpreted as the standard deviation of a parameter
estimation over multiple replications
- we use histograms and descriptive statistics to study a variable
- we often want to know if the variables are correlated
- Pearsons r correlation coefficient indicates the strength of a linear relationship between two
variables
- the correlation coefficient is calculated from the covariance between the variables and the
standard deviation of the variables
- the covariance expresses the linear relationship between the variables on the original scales of the
variables
cov(x,y) = rXY = cov(x,y) / (sd(x)*sd(y))
rxy = σxy / (sx * sy)
- if we have more than two variables we can summarise the linear relationships with a covariance
matrix
- variances are visible on the diagonal
• the variance of vocabulary is 135.292
Page 2
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 jelenawilliams. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $5.93. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
56326 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now