Stats 3.1-3.3

What can be said about a set of data with a standard deviation of zero

All the observations are the same value

What does it meanness if a statistic is resistant?

Extreme values (very large or small) relative to the data do not affect its value substantially

Median> Mean

For a distribution that is skewed left, which of the following is true

Mean> Median

For a distribution that is skewed right? Which of the following is true

Why do you think HUD uses the median?

HUD uses the median bc the data are skewed right

Which car

It has a lower sample standard deviation, hence more predictable gas mileage

Are any of the measures of dispersion among the rang , the variance, and the standard deviation resistant?

No, all these measures of desperation are affected by extreme values

Mean

Symmetric

A histogram of a set of data indicates that the distribution of the data is skewed right. Which measure of central tendency will likely be larger, the mean or the median? Why?

The mean will likely be larger because the extreme value in the right tail tend to pull the mean in the direction of the tail

What makes the range less desirable than the standard deviation as a measure of dispersion

The range does not use all the observations

False

The standard deviation is a resistant measure of spread true or false

Mean, mean, spread

The standard deviation is used in conviction with the ___ to numerically describe distributions that are bell shaped. The __ measures the center of the distribution, while the standard deviation measures the spread of the distribution.

Zero

The sum of the deviations about the mean always equals

Degrees of freedom

There are n-1 degrees of freedom in the computation of an unknown parameter, h is estimated by the mean. For each estimated the 1 degrees of freedom is lost

False

True or false: the standard deviation can be negative

False

When an observation that is much larger than the rest of the data is added to the data set, the value of the median will increase substantially

What is true of the coefficient of variation?

When converting units of measure, the coefficient of variation is unchanged

Trimmed mean

Yes because the extreme values do not affect it

True or False: a data set will always have exactly one mode

false