StuDocu.com STA10003 Cheat Sheet Foundations of statistics (Swinburne University of Technology) StuDocu is not sponsored or endorsed by any college or university Downloaded by Akshata Katarey (akshatakatarey@gmail.com)
Significant: P < 0.05 Correlation (Scatterplot): Direction Form Strength Outliers Not Significant: P > 0.05 Y= Constant + (SlopeX) Levene Significant Not Equal Variance Pearson's r: >0.5 Strong, 0.3-0.49 Mode, 0.10-0.29 Weak, <0.10 Ext Weak DV: Y Axis IV: X Axis p= The strength of the linear r/p r2= The amount of variability in the DV explained by the r/p of the linear variables Nuisance Variable: Unwanted factor on independent variable Confounding Variable: A factor that effects both DV and IV Levene Not Sig: Equal Variance Positive skewed tails to right - negative tails to left, Median better for skewed Z-score (Normal Dist) = (x-u )= o where x = value u= mean o= StdDev Cross-tabulations (IV: Column DV: Rows) IQR= Q3 - Q1 Outliers= 1.5 x IQR df= n-1 n= Sample size x mean (not normal dist) u=mean (normal dist) s= std dev (not normal dist) o= std dev (normal dist) Relative Risk: (x/xz) = (y/yv) Expressed as more or less likely where 1=No risk x d = mean difference Sd = Std Dev of the difference Odds Ration: (x/z)=(y/v) Expresses as higher or lower where 1= even odds When describing: Shape (Normal, Symmetric, skewed), Centre (Mean or Median), Spread(Std Dev) Outliers (1.5xIQR or >2s) Calc Stand Value z = x - 11 x x = Sample mean Jx = mean of sampling distribution Yes No Z Total(XZ) 0 0 x = StdDev of the sampling distribution How many StdDev is the sampling mean away from the sampling distribution (multiple samples) Use std error when assessing distribution of multiple sample means Cat A X Cat B Y V Total (YV) Total (XY) Total (ZV) Independent sampling E.G - Ours is bigger than yours- 1 Metric & 1 Categorical Variable - Box Plot, Graph of Means-Independent Groups no neg t-score A researcher hypothesised that the blood cholesterol levels of people who do not exercise regularly would be higher than those of regular exercisers. In a random sample of 78 adults, the average blood cholesterol level of the non-exercisers (x = 247.65mg/dl, s = 33.44mg/dL, n = 43) was higher than the average blood cholesterol of the people who exercise regularly ( x = 189.06mg/dl, s =35.96mg/dL, n= 35), and an independent samples t-test shows that the difference in the mean blood cholesterol levels is significant, t(76)= 7.44. p < . 001. The 95% Confidence interval shows that the mean blood cholesterol level for people who do not exercise regularly is between 42.9 and 74.3mg/dL higher than for people who do. As expected, the blood cholesterol levels of non-exercisers are higher than for those people who exercise regularly. Paired Sampling E.G - Our this is bigger than our that - 1 Metric & 1 Categorical Variable - Box Plot, Graph of Means-Repeated Measures It was hypothesised that the electricity bills for households when using