# Hcs 438

Pages: 2 (273 words) Published: July 16, 2012
Stats Notes Week Two
Describing Data
Mean-average (takes every value into account- Sum of all Values/total number of values=mean Median-what data is in the middle (exact middle value)?
Mode-what value occurs most frequently in the data?
Interval and Ratio Data
Nominal
Ordinal
Interval-best data
Ratio-best data
Measures of Variation
Outlier-high-end/low-end
Interpret the measures of central tendency-mean, median, mode Measures of variability-range, standard deviation (SD) =square root of variance is SD Standard Scores
Zscores-table of standard z scores
Tdistributions-test to see if variable A = variable B interval/ratio data/normal curve either they = each other or they do not-Mean of A/ Mean of B 2 tailed test is easier but yields less information than 1 tail Explanatory variable-explaining variable

Week 3 Quiz Chapters 4, 5, 6
Standard Deviation convert to percentages

Normal Distribution?
Rule for normal distribution. (MEMORIZE) Chapter 5
Normal distribution illustrating the 68%-95%-99.7%
About 68% of the values fall within 1 standard deviation of the mean… …About 95% of the values fall within 2 standard deviations… …and 99.7% of the values fall within 3 standard deviations. * Definition- about 68% (more precisely, 68.3%), or just over two-thirds, of the data points fall within 1 standard deviation of the mean. * About 95% (

Simple rule-called the 68-95-99.7 gives precise guidelines for the percentage of data values that lie within 1, 2, and 3 standard deviations of the mean for any normal distribution. If you do not have normal distribution, this does not apply