Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
18 Cards in this Set
- Front
- Back
|
What shape is a normal distribution?
|
Bell shaped
|
|
|
Is a normal distribution symmetrical or asymmetrical?
|
symmetrical
|
|
|
What sort of data is represented by a normal distribution?
|
Continuous
|
|
|
What does the area under the curve add to?
|
1
|
|
|
What is the relationship between the mean and the median?
|
Mean = median
|
|
|
What rule applies to normal distribution?
|
Empirical rule
|
|
|
Continuous random variable
|
a variable that can take on any value over a given interval
- measured, not counted - infinite number of possible values - e.g. height, weight, time |
|
|
What is the empirical rule?
|
68% of observations are within one standard deviation either side of the mean
95%of observations are within two standard deviations either side of the mean 99.7% of observations are within three standard deviations either side of the mean |
|
|
What happens if you change the standard deviation?
|
Changes the shape of the curve
|
|
|
What happens if you change the mean?
|
Changes the location of the curve
|
|
|
Standardised normal distribution table
|
Table of probabilities for a normal distribution with mean = 0 and standard deviation = 1
|
|
|
What must you do if the mean and standard deviation values are not 0 and 1?
|
Transform them into standard normal random variables
|
|
|
How do you transform numbers into standard normal random variables
|
Z = X - mean/standard deviation
|
|
|
What is the number of standard deviations a given value is away from the mean sometimes called?
|
Z-score
|
|
|
Z-score
|
The number of standard deviations a given value is away from the mean
|
|
|
Which characteristics must the data fit to be normally distributed?
|
- mean = median
- Central clustering (approx 68% of data within one standard deviation of mean) - small probability of data being in tails - most data within + or - 3 or 4 standard deviations of the mean |
|
|
How is normally distributed data usually plotted?
|
- Histogram
- Frequency Polygon - Boxplot - Stem and Leaf |
|
|
What are the skewness and kurtosis values for normally distributed data?
|
0
|
