Statistics all important details

Statistics most important details
Cheatsheat
Descriptive Difference Relations
statistics
Nominal Mode X2
Ordinal Median, range X2
Scale or Mean, stdev T-test Correlation,
Interval / ratio regression
P <..05  significant

P is smaller than 5% = significant
P is bigger than 5% = not significant

Descriptive statistics
1. Measure of centre
 Mode: most frequently observed value
 Median: mid-point – 50/50 (rank order your data)
 Mean: average
 Standard deviation: describes variation of a distribution, these two numbers describe /
summarize a group of data
 T-test: difference between 2 groups
 Chi square: relationship
 Correlation: relationship
 Regression: prediction

2. Measure of spread
Range: lowest – the highest value  ordinal
ST Dev  scale

Measurement levels:
Nominal: labels – variable with values with no numerical value (gender)
Ordinal: Ranking (star rating)
Scale: Same distance between number. (Age, length, income)

Scale is also interval / ratio: Same distance between number.
 Ratio has a zero point

Categorial: nominal, ordinal
Numerical: interval, ratio