The Normal Curve Flashcards
0
Q
Asymmetrical Curve
A
- The values of variables occur at irregular frequencies
- The mean, median and mode occur at different points
- Exhibits skewness
1
Q
Symmetrical Curve
A
- Skewness - Normal or bell shaped curve with no skew.
* Mesokurtic - normal distribution with no kurtosis.
2
Q
Percentage of cases under portions of the Normal Curve to the RIGHT»
A
0SD = Mean 0SD -> 1SD = 34.13% 1SD -> 2SD = 13.59% 2SD -> 3SD = 2.14% 3SD -> = .13%
0SD+1SD = 34.13% 0SD+1SD+2SD = 47.72% 0SD+1SD+2SD = 49.86% 0SD+1SD+2SD+3SD = 49.99%(50%)
3
Q
Percentage of cases under portions of the Normal Curve to the «LEFT
A
0SD = Mean
-1SD <- 0 = 49.99% (50%)
4
Q
Normal Curve Examples
A
- IQ: Mean = 100, SD = 15
- Exams:
- Midterm 1: Mean = 28, SD = 4
- Midterm 2: Mean = 30, SD = 2
5
Q
Normal Curve: How to compute:
A
unsure yet
6
Q
Z-scores
A
standardized scores that taken to the z-score table reveal percentage of scores.
7
Q
How to compute z-scores
A
Formula: Standard score, z = X - µ / SD µ = Mean (mu) x = score SD = standard deviation (sigma) z = individual score minus mean both divided standard deviation.
8
Q
What does the z-score tell you
A
- How far a score is from the mean
* Allows you to compare
9
Q
Z-Score Examples
A
•Exam 1:
Mean = 60, SD = 15, X = 70, solve for Z.
•Exam 2:
Mean = 75, SD = 2, X - 80, solve for Z
10
Q
Top 25% of a z-score
A
Bottom 25%
11
Q
IQ higher than 89% of others
A
whats the IQ
