Chapter 6- The Normal Curve, Standardization, and z Scores Flashcards
What is a normal curve?
A normal curve is a specific bell shaped curve that is unimodial, symmetric, and defined mathematically
What does the normal curve describe?
A normal curve describes the distributions of many characteristics and measures that vary.
What occurs when the sample size increases?
When the sample size increases, the shape of the distribution become more like the normal curve.
What is standardization?
Standardization coverts individual scores to standard scores and allows us to determine where the score falls in realation to other scores
How do you calculate the z score?
The z score is calculated by subtracting the observation from the mean then dividing the number by the standard deviation SD
When the observation is above the mean, will the score be negative or positive?
The score will always be positive
When the observation is below the mean, will the score be negative or positive?
The score will always be negative
When the observation is the same as the score, what is the z score then?
The score will be 0
Converting z scores will always have a mean of _____ and a standard deviation of _____
0, 1
Will standardizing scores change the shape of the distribution?
No, standardizing does not change the shape of the distribution
How do you calculate a raw score if you are given the z score, SD and mean?
Z score x SD+mean= Raw Score
What are population distributions?
Population distributions are theoretical and assumed to be normal
What are sample distributions?
Sample distributions are observed and as the population increases, the normal distribution increases
How do you calculate percentiles of normal distribution?
If number is 0, the percent is 50. If the number is negative, start counting from right. If the number is positive, count from left (count from opposite side)
What is the central limit theorem?
As the sample size increases, the sampling distribution of the mean will approach a normal distribution
