# GLHLTH 371 Lecture Notes - Lecture 7: Standard Score, Central Tendency, Statistical Parameter

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Analyzing Data Using Statistics

****need to know how to calculate all measures of central tendency and measures of variability

I. Descriptive Statistics

a. Summarize raw data

b. Frequency distribution: table that shows number of scores that fall within each category

c. Histogram: graphical representation of a frequency distribution

c.i. Used when scores are on an interval or ratio scale (continuous variables)

II. Descriptive Statistics for Continuous Variables

a. Measures of central tendency: in a normal distribution, all three are the same

a.i. Mean

a.ii. Median

a.iii. Mode

b. Measures of variability

b.i. Range: difference between smallest and largest score

b.ii. Variance: index of average variability

b.iii. Standard deviation (SD): index of variability in scores in original scores; can be

used to describe variability in meaningful terms; whereas variance isn’t in units

of your measure

b.iv. Z-score: a standard score, used to describe how far a participant’s score varies

from the mean in terms of SDs; z = (score-mean)/standard deviation

b.iv.1. **1 SD from mean (both directions)= 68%; 2 SDs: 95%; 3 SDs:

99.7% (know these numbers)

III. Inferential Statistics

a. Used to draw inferences about a population based on easurement from a sample

b. These are assumptions; we hope that these are accurate reflections of the population

(parameter); sample is a statistic

c. Population parameter

c.i. Quantitative summary of variable in the population

c.ii. Has a fixed value that does not vary

d. Sample statistic

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