Z-Score
Density Curve
Transformations
Empirical Rule
Miscellaneous
100

If a value has a negative z-score, where is the value in relation to the mean?

Below the mean

100

A density curve for rolling a die (all outcomes equally likely) would have what shape?

uniform

100

Adding a constant a to each observation changes these two things

Mean and median

100
The Empirical Rule says given normal distribution approximately ___% of all obserations fall within one standard deviation of the mean
What is 68%
100

Gathering the heights of every 10 year old in Malden will result in this type of distribution

Normal curve

200

The equation to find z-score

(value-mean)/(standard deviation)

200
In a symmetric density curve these two things are the same.
What is mean and median
200

These 4 measures stay the same after adding a constant a to each observation

IQR, standard deviation, range, shape

200
Given an approximately normal distribution, ____% of all values are above the mean.
What is 50%
200

percentile is the percent of the observations _________ a given value. (less than, equal to, greater than)

What is less than

300

How do you compare values from two different distributions?

Compare their z-scores

300
The mean of a density curve skewed left is pulled towards this side
What is left
300

After multiplying each observation by a constant "b" this measure does not change.

What is shape (i.e. whether a graph is skewed, symmetric, etc.)

300

Given approximately normal distribution with a mean 35 and standard deviation 5, approximately 99.7% of all values are contained in this interval.

20 to 50

300
A ___________ is a curve on or above the horizontal axis that has area of exactly 1 underneath it
What is density curve
400

The z-score for x=25 given approximately normal distribution with mean 32.5 and standard deviation 5.5

What is -1.36

400
The total area under the density curve
What is 1
400

After dividing each observation by a constant "b" these 5 measures are affected

Mean, median, range, IQR, standard deviation

400

Approximately what percent of values lie with in -2 standard deviations and +1 standard deviation of the mean

What is 81.5%

500

What is a z-score?

How many standard deviations a value is away from the mean

500
A special density curve that is symmetric, single-peaked, and bell-shaped
What is a normal curve
500
After adding "a" and multiplying "b" to every observation, this happens to the standard deviation. (be specific)
What is the standard deviation is multiplied by "b"
500

Approximately _____% of values are greater than 2 standard deviations above the mean or less than 3 standard deviations below the mean given approximately normal distribution

What is 2.65%

500

How can you assess whether a distribution is normal?

Find the percentage of data within 1, 2, and 3 standard deviations and compare to the empirical rule

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