STAT 301 Lecture Notes - Normal Distribution, Point Estimation, Standard Deviation
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There is not just one t-distribution for each mean and standard deviation, but a family of distributions. The t-distribution is more spread out and flatter at the center than the standard normal distribution. The t-distribution"s shape depends on the sample size, n. As sample size increases, the t-distribution approaches the normal distribution. Constructing a ci x is the point estimate. Critical value is from t-portion of table 3. Based on confidence level and degrees of freedom (df), where df = n-1. N t5 would be a t-distribution with 5 degrees of freedom. )2 n = ( n = minimum sample size. Zcrit = z value for desired level of confidence. If a s. d. in a previous study is thought to be reliable, it can be used in the current study to provide an appropriate sample size. If you have estimates of the largest and smallest values in the population, let s =
