MAT 121 Lecture Notes - Lecture 2: Simple Random Sample, Level Of Measurement, Blood Type
5 May 2018
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Data
Statistics is the study of the collection, organization, analysis, and the interpretation of Data
which are collections of observations (such as measurements, gender, survey responses)
Quantitative or Numerical data consist of number representing counts or measurements, and
can be further described by two types.
● Discrete data is counted ( A randomly selected car has 6 cylinders)
● Continuous data is data that is measured (The volume of cola in a can of coke is
12.3 oz)
Qualitative or Categorical or Attribute data consist of names or labels that are not numbers
representing counts or measurements. For example,
● The genders of students
● Blood type, favorite color, names…
● These use the nominal and ordinal (can order the labels) scales.
Population vs Samples
A population is the entire collection of all items (scores, people, measurements, and so on) to
be studied. Any characteristic that describes a population is called parameter, usually denoted
by a Greek Letter.
● The average if a population is denoted by μ or (mu).
A sample is a subgroup of a population. A characteristic that describes a sample is called a
statistic, usually written as a Latin letter.
● The average of a sample is denoted by ẍ (x bau)
Statistics are most often used to estimate the value of the unknown parameters.
Example:
Consider the problem of estimating the average weight of all 18 year old girls.
What is the population? ALL 18 year old girls.
What is the parameter of interest? The average weight.
Determine if the given value is a statistic of a parameter?
A sample of 20 SU professors is selected and their average age is 45 years.
45 years is a statistics
20 is the sample size of the statistic.
In a study of all professors at a college it is found that 85% own a laptop.
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Statistics is the study of the collection, organization, analysis, and the interpretation of data which are collections of observations (such as measurements, gender, survey responses) Quantitative or numerical data consist of number representing counts or measurements, and can be further described by two types. Discrete data is counted ( a randomly selected car has 6 cylinders) Continuous data is data that is measured (the volume of cola in a can of coke is. Qualitative or categorical or attribute data consist of names or labels that are not numbers representing counts or measurements. These use the nominal and ordinal (can order the labels) scales. A population is the entire collection of all items (scores, people, measurements, and so on) to be studied. Any characteristic that describes a population is called parameter, usually denoted by a greek letter. The average if a population is denoted by or (mu). A sample is a subgroup of a population.
