The Normal Curve Flashcards
What does a boxplot represent?
It shows the median, range, and interquartile range to visualize central tendency and dispersion.
What is included in a five-number summary?
Lowest score (L), highest score (H), Q1 (1st quartile), Q2 (median), and Q3 (3rd quartile).
What is a unimodal distribution?
A distribution with one peak (mode).
How does skewness affect the mean?
The mean is pulled in the direction of outliers.
What are the characteristics of a normal curve?
Bell-shaped, unimodal, symmetrical, unskewed, with mean = median = mode.
What happens to the shape of the normal distribution as standard deviation changes?
The shape of the curve becomes wider or narrower.
What are the three types of kurtosis?
Leptokurtic (thin and peaked), Platykurtic (flat and wide), Mesokurtic (normal).
What percentage of cases fall within ±1 standard deviation in a normal distribution?
68.26%
What percentage of cases fall within ±2 standard deviations?
95.44%
What percentage of cases fall within ±3 standard deviations?
99.72%
What is a Z-score?
The number of standard deviations a raw score is from the mean.
What does Column A in the standard normal table represent?
The Z-score.
What does Column B represent?
The area between the mean and the Z-score.
What does Column C represent?
The area beyond the Z-score.
How do you find the area above a positive Z-score?
Use Column C in the standard normal table.
How do you find the area below a positive Z-score?
Add Column B’s value to 0.50.
How do you find the area below a negative Z-score?
Use Column C directly.
How are areas under the normal curve related to probability?
They represent probabilities as proportions between 0.00 and 1.00.
What does a higher probability value indicate?
A higher probability means the event is more likely to occur.
What is a helpful strategy for solving probability problems?
Draw the normal curve, mark the mean, place the Z-score, and shade the area of interest.
How does the sign of the Z-score affect calculations?
It indicates whether the score is above (+) or below (-) the mean.
