M3 Flashcards
- These are characteristics that describe the middle or most commonly occurring values in a series
- They are used as summary measures for the series that attempts to describe a whole set of data with a single value that represents the middle or center of each distribution
MEASURES OF CENTRAL TENDENCY
often called the average, of a numerical set of data, is simply the sum of the data values divided by the number of values
Mean
sum of value / num of value
mean
the number that falls in the middle position once the data has been organized
Median
(n+1) / 2
Median
a set of data is simply the value that appears most frequently in the set
Mode
2 levels of measurement
Qualitative and Quantitative
level of measurement: data consists of values into nonnumeric categories.
I.e. subjects in college, education level
qualitative
data consist of values representing counts or measurements. It can be measured by tool, scale, or count
quantitative
2 Types of qualitative data
1.Nominal level (by name)
2. Ordinal level (by order)
Type of qualitative data: No natural ranking or ordering of the data exists
Nominal level
Type of qualitative data: Can’t get a precise mathematical difference between levels. ( Could be coded mathematically)
Ordinal level
_____ can take on any value in an interval but could also have decimals (weight, home value, height and 2.45) while discrete can take on only particular values (shoe size, number of students and number of prerequisite courses).
continuous
Occurs when a numerical scale does not have a ‘true zero’ start point.
▪ Differences make sense, but ratios do not.
▪ 100° Fahrenheit is not twice as hot as 50° Fahrenheit.
▪ Does 0° Fahrenheit represent an absence of heat?
▪ Equal interval
▪ EXAMPLES : Temperature, Calendar year and IQ test
Interval (subtraction level)
Occurs when scale does have a ‘true zero’ start point.
▪ At this level, both differences and ratios are meaningful.
▪ 2 oz glasses of water IS equal to one 4 oz glass of water “ 4oz of water is twice as much as 2 oz of water.
▪ 0 oz of water is a ‘true zero’ as it is empty, absence of water.
▪ Ratios involve division (or multiplication) rather than addition or subtraction.
▪ Examples: Mass, Length and Time Levels of Measurement
Order
