Download basic statistics z-score worksheet

BASIC STATISTICS Z-SCORE WORKSHEET
Finding z-score step-by-step...
FIRST, find the mean of the data set.
THEN, find the standard deviation of the data set.
x  mean
AFTER THAT, the formula for z is z 
. Note: Each point in the
sd
set will have its own z-score.
1.) Is a point with a z<0 above or below the mean? ____________________
2.) Is a point with a z such that  1  z  1 typical or unusual? ____________________
3.) Is a point with a z > 3 typical or unusual? ____________________
4.) A point with z=0 equals the ____________________
5.) A symmetric, bell-shaped data set has a mean of 12 and a standard deviation of 4.
Find the following:
a.) P(x< 7) = P(z < _____) = ________
b.) P(x > 18) = 1 – P(z<_____) = ________
c.) P(10<x<16) = P(z<_____) – P(z<_____) = ________
6.) A symmetric, bell-shaped data set has a mean of 80 and a standard deviation of 5. You
will need to write your own steps for this one! Find the following:
a.) P(x<92) = ________
b.) P(x>75) = ________
c.) P(78<x<90) = ________
7.) A symmetric, bell-shaped data set has a mean of 25, a standard deviation of 1.7 and a
sample size of 500. Find the following: (Round appropriately)
a.) The number of data points less than 22: ____________
b.) The number of data points between 23 and 27: ____________
c.) The number of data points greater than 28: ____________
8.) A symmetric, bell-shaped data set has a mean of 200 and a standard deviation of 6.
Find the following: [Hint: Use the formula bound = z*sd+mean]
a.) 90% of the data will be less than ____________.
b.) 70% of the data will be greater than ____________.
c.) 98% of the data will be between ____________ and ____________.
Review Questions
12.) Make a frequency table out of this data set: A sample of the number of credits
completed by college Juniors: {15, 28, 17, 19, 22, 27, 16, 14, 14, 12, 22, 17, 19, 40, 27,
18, 30, 29, 17, 28, 18}. Number of classes = 4. Include the columns Class, frequency,
midpoint, f*midpoint. Then, find the mean using the frequency table.