Descriptive statistics Flashcards
What types of data fall under qualitative and what types fall under quanitative
Qualitative- ordinal nominal
Quantitative- ratio and interval
Describe types of Nominal Data
They have none of the properties of a real number system. Gender Hand dominance Presence or absence of a disease Diagnostic categories Classification based on discrete characteristics (e.g., hair color) Any yes/no distinctions Location of damage in the b
Describe ordinal data and provide examples
All the characteristics of a nominal scale, plus there is a ranking among the categories. It indicates whether person has more or less of a certain quality.
None, Mild, Moderate, Severe pain
Acute phase, sub-acute phase, chronic phase
Hypotension, normo tension, hypertension
Minimal, moderate or maximal assistance
Describe interval data and provide examples give (just think like the VAS scale)
Interval scale
They have real number system properties of order and distance, but they lack a meaningful origin. Designates an equal-interval ordering, no true zero point
Temperature (Degrees F) 70, 75, 80, 85, 90, 95.., or 71, 72, 73, 74, 75…
Height
Satisfaction scales (Likert scales): Strongly agree, agree, neutral, disagree, strongly disagree
……………..
Describe Ratio data there is an exact true zero point and give examples
Ratio scale They exhibits all three components of a real numberdo system: order, distance, and origin. Weight Size of an object BMI ROM Girt measurement
Measures of Central Tendancy what type of scale do you use for Nominal Data (Mean, Median, or Mode) what Ordinal, Interval, or Ratio
Nominal- mode (how often circles a certain catagorey on a given scale
Ordinal- (Median ) These are ranks but without numbers
Interval no true zero point ( like temp, or distance) (mean)
Ratio (stops exaclty at zero and doesn’t go below zero on the scale ) like ROM they use (mean)
Both Quanitative data uses mean causse its numbers
Describe difference between continuous and discrete data
Discrete data: Data are in whole numbers and measured by nominal or ordinal scales: Number of children Number of times you been married Date of birth, etc. Continuous data: Data may (but are not required) take on fractional values: Temperature (37.5 degrees) Age Body Mass Index (BMI)
Descride the difference between descriptive data and inferential data
Descriptive: are used by researchers to report on populations and samples.
Central Tendency measures.
Variation or Variability measures.
Inferential: which test for significant differences between groups and/or significant relationships among variables within the sample.
t-ratio, chi-square, beta-value, relationship.
Describe descriptive characteristics
measures and describes characteristics of groups without drawing inferences about the population in general.
gives numerical and graphic procedures to summarize a collection of data in a clear and understandable way.
Describe differences between Central tendency and Variation
Central Tendency (or Groups’ “Middle Values”) Mean Median Mode Variation (or Summary of Differences Within Groups) Range Interquartile Range Variance Standard Deviation
Is mean affected by outliers and if so what measure of central tendancy should you use
yes it is so if the data represents a normal distribution curve use the mean however, if the data is skewed and does not represent a typical bell shaped curve use the median,
should you use median if the distribution is skewed
yes.
Describe Variance , dispersion, range, SD and these are all just examples of Variability
Variability is the differences among scores- shows how subjects vary:
Dispersion: extent of scatter around the “average”
Range: highest and lowest scores in a distribution
Variance and standard deviation: spread of scores in a distribution.
Standard deviation: how much subjects differ from the mean of their group
Measures how much subjects differ from the mean of their group
The more spread out the subjects are around the mean, the larger the standard deviation
Sensitive to extremes or “outliers”
It is defines as the square root of the variance
Tell me the percentages for the SD away from the mean like 68 is one SD from mean what about the other two.
you add percentages, you will see that approximately: • 68% of the distribution lies within one standard deviation of the mean. • 95% of the distribution lies within two standard deviations of the mean. • 99.7% of the distribution lies within three standard deviations of the mean.These percentages are known as the “empirical rule”.
Describe descriptive characteristics
measures and describes characteristics of groups without drawing inferences about the population in general.
gives numerical and graphic procedures to summarize a collection of data in a clear and understandable way.
