University:
York University
Course:
PSYC 2021 | Statistical Methods I
Academic year:

2024
Views:

168

Pages:

4
Author:

Nick T.

Lab I Order of Operations (Pemdas) P - parentheses E - exponents (powers; square roots) MD - multiplication and division (left to right) AS - addition and Subtraction (left to right) Please Excuse My Dear Aunt Sally 7+(6x5^2+3)= -166 Summnation Notation Summnation: the operation of adding a sequence of numbers Notation: Symbolic representation (i.e., Greek letters) Summnation notation = Summnation notation Summuation notation = Shorthand for 'adding things together' Σ = Sigma (sum) experiment: infant birth weight data on four babies to the nearest pound X= infans birth weight x:8,7,5,10 -8x=8+7+5+10=36 Σ(x-3) -Σ(x-3)=(8-3)+(7-3)+(5-3)+(10-3)=16 (2x)^2 -(Σx^2)=(8+7+5+10)^2=900 5x^2 -Σx^2=8^2+7^2+5^2+10^2=238 Levels of Measurement qualitative: qualities; can't actually be measured nominal: distinct Categories (i.e., major, hair color, etc.) quantitative: information about quantities; can be measured and numerically ordered Ordinal: rank ordered; interval between items unknown (i.e., beauty pageant winners) interval: Continuous data; has ordinal property and numerically equal intervals between items; no true zero (i.e., IQ Scores, temperature) ratio: has interval properties and true zero; when the variable equals zero, there is none of that variable (i.e., weight, height) Frequency Tables Frequency: number of times a data value occurs frequency table: table that displays a pattern of frequencies gives a Series of data tendencies illustrates the pattern of scores helps create a histogram for data Step 1: Column of each possible value Step 2: Column of how many times each value appeared (frequency) Step 3: Column of percentages of scores for each value (frequency/total number of scores) x 100 Frequency Distributions frequency distribution (histogram) a graph plotting values of observations on the X(horizontal) axis bar shows how many times each value occurred in the data set Distributions normal distribution (Symmetrical) bell shaped curve with Scores distributed symmetrically about the mean (average) Scores are very frequent at the center; decrease in frequency as you move outward (toward the tails) Skewed distributions (non-normal) Scores that are asymmetrical; pile up at tails positive skew tail is on the RIGHT negative Skew tail is on the LEFT bimodal distributions two peaks within the same distribution uniform distribution equal probability of Scores throughout the distribution