PSYC 1010 Chapter Notes - Chapter 9: Confidence Interval, Standard Deviation, Null Hypothesis
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Chapter 9- the single-sample t test & paired-samples t test. The t test tells us how confident we can be that what we have learned from our samples generalizes to the larger populations. Estimating population standard deviation from the sample. Use the standard deviation of the sample data to estimate the standard deviation of the entire population. We subtract 1 from the sample size in the denominator to correct for the probability that the sample standard deviation slightly underestimates the actual standard deviation in the population. Two steps to calculate the estimated standard deviation for the population: calculate the sample mean, use this sample mean in the corrected formula (above) for the. Calculating the standard error for the t statistic standard deviation. We need to make our spread smaller to reflect the fact that a distribution of means is less variable than a distribution of scores. Using standard error to calculate the z statistic.
