SECTION 6C HIGHLIGHTS
Vocabulary: Statistical Inference, Normal Distribution (Bell Shaped Curve), 68-95-99.7 rule, Percentile, z-score.
Assignment: Read about the Normal Distribution in section 6C of the
text. Do pp. 410-412
RQ(1,2), BSC(11-24,29-32,35,36),
WP(46).
Web Project #46 Link: SEE A NORMAL DISTRIBUTION FORMED
Normal Distribution Calculator (Area between z-scores)
Notes:
A Statistical Inference is an inference about the population parameters from
sample statistics.
A special type of symmetric distribution of a single variable has a bell shape. This type of distribution is called a Normal Distribution. All Normal Distributions have this basic bell shape, but the differ slightly depending upon the mean and the standard deviation of the distribution.
The 68-95-99.7 rule for a Normal Distribution involves the following:
About 68% of the raw data points
fall within 1 standard deviation of the mean.
About 95% of the raw data points
fall within 2 standard deviations of the mean.
About 99.7% of the raw data points
fall within 3 standard deviations of the mean.
A Percentile score is information that indicates the percent of raw data points that fall at or below a certain score. This can be found from the table on page 514 if the z-score for the score is calculated. the z-score is calculated as follows:
z-score = (value of data point - mean of data)/standard deviation of the data
Skills to be mastered:
1. Apply the 68-95-99.7 Rule to find percentages in a normal distribution.
2. Find the z-score for a data value.
3. Read a z-score table to find percentile.