Kinesiology 2032A/B Lecture Notes - Lecture 14: Confidence Interval, Prefrontal Cortex, Random Assignment
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Ex. average height of 9 individuals may be very different from the average height of 30,000 people. An interval of values within which there is a given level of confidence (ex. 95% confidence that the true value lies within this interval around the obtained sample result. The results from the survey are accurate within 3 percentage points, using a 95% level of confidence . Ask random sample of students if they prefer to study at home or school. Actual population value is probably b/w 58% and 64% There will always be a small chance the value is outside that range. If you only have a sample population your result may be an error. Confidence interval = info about the likely amount of error. Note: we can be 95% confident in our results but there is always a chance we"re wrong. Large sample size = reduce size of confidence interval.