STA_Notes_8.27.07

# STA_Notes_8.27.07 - ACT Mean 21 Std Dev Of 6 Which is...

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STA Class 20:48:26 2.7 Numerical Measures of Relative Standing o 1. p th percentile A number such that p% of observations fall below it and (100 – p)% fall above it. o Ex: SAT math score is the 84 th percentile Median—50 th percentile o 2. Z-score ***Will use extensively in the remainder of this course*** Sample z-score (figure 2.7-1) Population z-score (fig 2.7-2) o A z-score tells how far the observation is from the mean. Z distribution is called the standard normal distribution (mean set at 0) Negative—below the mean Positive—above the mean Zero—at the mean o Observations with a relative standing greater than I3I are considered unusual (outlers). o EX. SAT: Mean 1000, Std. Dev. Of 200

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Unformatted text preview: ACT: Mean 21, Std. Dev. Of 6 Which is better, a score of 1270 on the SAT or a score of 28 on the ACT? If the top 2.5% of students that take the SAT are offered a scholarship, what score would you need on the SAT to get a scholarship (SAT scored are mound shaped)? STA Class 20:48:26 Fig 2.7-3 1. SAT score is better 2. A score of 1400 • Summary Ch 2 o Calculate: mean, median, mode, standard, deviation (population or sample), variance (population or sample) o Know comparison of mean and median o Calculate and interpret z scores o Know 2 rules for interpreting standard deviation and be able to use the rules (Chebyschev and Empirical) o Percentiles....
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STA_Notes_8.27.07 - ACT Mean 21 Std Dev Of 6 Which is...

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