Probability, sampling and distribution 0.0 / 5 ? PsychologyProbability, sampling and distributionUniversityNone Created by: francesca_321Created on: 25-04-17 14:20 What is the probability theory? Branch of mathmeticians interested in random phenomena 1 of 29 How is height of distribution? Y= peak x e - (X - U) / 2O2 2 of 29 What does the X, Y, U and O suggest? X= desired score, Y= Frequency of that X, U=mean of population and O standard of population 3 of 29 What is the peak of distribution? Peak = N/ O (square root) of 2pi 4 of 29 What is a skew? Where the curve goes down, mode, median and mean 5 of 29 What is a negative skew? When the mode, median and mean go down 6 of 29 What is the co-efficient of skew? users differences in median and mode 7 of 29 How is the Skew calculated? 3(mode - median) /standard deviation 8 of 29 When is negative skew? Median > mean 9 of 29 What is a positive skew? Mean > median 10 of 29 What is a parametric test? Estimates of population parameters suh as mean and Standard deviation, mean and standard deviation accurately represent population distribution 11 of 29 How can data be transformed? We can transform data by performing math operations on all scores, 12 of 29 What can transforming data do? Reduce outliners 13 of 29 What can be done to data? Log every data point and perform stats tests 14 of 29 What are Z scores? Transforming data is useful in viewing standardised data 15 of 29 For example? Z = score - mean / S 16 of 29 What can Z scores tell us? How many Standard deviations we are above or below the mean value 17 of 29 What is a sampling error? Randomly drawn sample from a populations of values 18 of 29 What can you do? Estimate parameters of the original population 19 of 29 However? The mean of each sample differs fom the mean of the population, this difference is called sampling error 20 of 29 What is the standard error of the mean? Measure of how confident we are that we know the true population mean 21 of 29 What is the dependent variable/ Variability of the original data 22 of 29 What is the number of data used to what? Scribe mean 23 of 29 How do you work out the SEM? S/ Squared root of N 24 of 29 What is standard deviation? The amount scores vary 25 of 29 What is Standard error of the mean? Confidence that we know the true population mean 26 of 29 What is confidence interval? 95% liklihood of included true mean 27 of 29 How is the confidence Level calculated? C.L.95 = mean +- 1.96 x SEM 28 of 29 What are error bars? Non overlapping error bars imply significant difference 29 of 29
Probability distributions. The normal distribution. Deriving probabilities from the distribution 0.0 / 5
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