Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (.025) and its Z score = 1.96.
95% = mean ± 1.96 SEm
The trends in international mathematic and science study (TIMSS) in 2007 examined eighth grade proficiency in math and science. The mean mathematics scale score for the sample of eighth grade students in the US was 508.5 with a standard error of 2.83. Construct a 95% confidence interval for the mean mathematics score for all eighth grade students in the US.
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