Normal Curve and Z-Scores

Question 1

What are three fundamental characteristics of a normal distribution?

Answer 1

• unimodal
• symmetrical
• asymptotic

Question 2

Why is the normal distribution important?

Answer 2

It allows us to predict the probability of scores falling in a certain range (links data to probabilities)

Question 3

What are two types of deviations from normality?

Answer 3

Positive skew

Negative skew

Question 4

What is probability?

Answer 4

The likelihood of an event occurring
# of outcomes/total # possible outcomes
forms a direct link between samples and the population that they come from

Question 5

What is standardization?

Answer 5

The process of converting a raw score to a standard score, which is a metric more easily interpretable.

Question 6

How do you interpret a z-score?

Answer 6

A type of standardized score
Expressed the value of the score in terms of how many SDs it falls from the mean
Raw score = mean/SD

Question 7

How to determine meaningfulness of data

Answer 7

statistical significance
practical significance
confidence interval

Question 8

standard error

Answer 8

standard deviation of the frequency distribution

amount of noise we expect to determine strength of signal

Question 9

law of large numbers

Answer 9

larger the sample size, more probable that sample mean will be close to the population mean