statistics 216 Exam 1
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What are Zscores and what do they tell you? and what is the formula?
 Standardize scores and they tell you how many standard deviations above or below the mean a score is.
 The formula is: (score  mean)/ Standard deviation

what does shifting do to zscores
 adding or subtracting a constant from every date value
 the 5number summary  increased by the constant
 median  increased by constant
 mean  increased by constant
 IQR  stays the same
 Standard deviation  stays the same

What does rescaling do to zscores
 multiplying or dividing all the values by a constant
 5 # summary: mult. or divide by constant
 Median: mult. or divide by constant
 Mean: mult. or divide by constant
 IQR: mult or divide by constant
 Standard deviation: Multiplied or divide by constant

What is the % rule for the normal model of standard deviation
68  95  99.7 Rule

What does normalcdf function on the calculator do and how do you use it?
 calculates area under a normal curv
 normalcdf( start, end, mean, standard deviation)

What does the invnorm calculator function used for?
 Can find zscores in reverse
 find a certain percentile
 invnorm (proportion, mean, standard deviation)

how can you find the IQR using a normal standard deviation model?
Take the 25th percentile  the 75th percentile

With scatter plots what variable do you put on the xaxis and what one on the yaxis
 the explanatory variable goes on the xaxis
 the responsive variable goes on the yaxis

What is the correlation
the measure of the strength of the linear association
It is very sensitive to outliers
The more association the closer to 1 the correlation will be

When do you use a scatter plot?
When you want to determine the relationship between QUANTITATIVE variables