PSYC 305 Lecture Notes - Lecture 2: Confidence Interval, John Tukey, Libido

• School: McGill University
• Department: Psychology
• Course: PSYC 305
• Professor: Matthew Dean Graham

Document Summary

Obtained probability is less than critical p-value: reject the null hypothesis, results are statistically significant. Obtained probability is greater than critical p-value: fail to reject the null hypothesis, results are not statistically significant. How to estimate the population standard deviation (cid:894) (cid:895) Xsample = [8, 12, 16, 12, 14: at the end of : gives sum of squares. Calculate the sample mean: = x(cid:1866) = 8+12+16+14/5 = 12. 40. Use in the corrected sd formula: (cid:1830)= (cid:4666)x (cid:4667)2(cid:1866) (cid:883, unbiased estimation with a n-1. This gives the sample standard deviation which can be used to infer the population standard deviation . Using sd to estimate the standard error of the mean (sem) Use the in the corrected sd formula: (cid:1831)= (cid:1830) (cid:1866) . = 1. 33: we never use n-1 for standard error of the mean because the estimation was already performed in the sd. But in the real world, population parameters are almost never known.