PY 211 Test 2 Chapter 5

it allows for more intuitive interpretation with respect to the data than does the variance.

We generally like the standard deviation when we are trying to describe a sample of data because

it leads to an unbiased estimate of the sample variance

We normally compute the variance using N-1 in the denominator because

a quartile

A "hinge" is another word for _______.

to understand what a distribution of data looks like

A boxplot is better than a statistic such as the mean when your purpose is

35.4

A data set of intelligence scores was collected from high school seniors. The IQ scores ranged from 82 to 113. Which of the followingis probably NOT a reasonable estimate of the standard deviation?

has been truncated equally at the two extremes

A trimmed sample is one that

both a and b (can be an extreme score and can be an error that snuck into data)

An outlier..

decrease the variability as the sample size increases.

As you increase the number of observations in a sample from 50 to 500, you are most likely to

more effect on the variance than scores at the center of the distribution

Data points at the extremes of the distribution have

outliers

Data points that lie outside the whiskers in a box plot are often referred to as

The degree to which individual data points are distributed around the mean

Dispersion refers to..

all of the above

Errors that can lead to outliers can occur in

1

Given the numbers {1,2, and 3} the standard deviation is

all of the above

If I continue to draw observations from a population and recalculate the mean each time I add an observation, the mean will approach _____ as the sample size increases.

66.7% of them

If the average adult male in the United States is 5' 9" tall, and the standard deviation for height is 2", approximately how many adult males would you expect to be between 5' 7" and 5'11" tall?

positively skewed

If the whiskers on a box plot are much longer on the right than on the left, we would suspect that the distribution is ..

interquartile range

If we eliminate the top and bottom 25% of the data and take the range of that remains we have the

the average deviation from the mean is about 8 points.

If we know that a set of test scores has a mean of 75 and a standard deviation of 8, we would conclude that

multiply the mean and the standard deviation by the constant

If we multiply a set of data by a constant, such as converting feet to inches, we will...

all but the most extreme values

In a box plot the width of the box encompasses

the standard deviation of number of family members would probably be relatively high.

The US Census Bureau collected data on family composition and found that samples from different parts of the country gave very different results for the mean number of family members living in households. If all of the data were combined to one data set,

The value of the standard deviation in a population

The difference between s and SD is that SD is

it discards too much of the data

The disadvantage of using an interquartile range is that

hinge location

The equation "median location +1/2" is used to calculate the..

contains the middle 50% of scores in a data set

The interquartile range

usually an unknown that we try to estimate

The population variance is

positive and negative deviations will balance out

The problem with measuring dispersion by merely averaging all the deviations between each score and the overall mean is that

the difference between the highest and lowest score

The range is ..

1.0

The standard deviation for the numbers 8,9, and 10 is

all of the above

The university counseling center has treated a large number of students for depression. They find that the standard deviation of depression scores for their pool of students is substantially higher after treatment than before treatment. The most likelyexplanation is

Average of the squared deviations from the mean

The variance can best be thought of as the

represents the sample median

The vertical line in the center of a box plot

contain all data points outside the box except the outliers

The whiskers in a box plot

how much the stock price is likely to fluctuate

People in the stock market refer to a measure called the "standard deviation," although it is calculated somewhat differently from the one discussed here. Itis a good guess that this measure refers to

a statistic whose average is very stable from sample to sample

What do we mean by unbiased statistic

less biased

When calculating the standard deviation we divide by N-1 rather than N because the result is

The density

Which of the following is NOT a measure of variability?

range

Which of the following is NOT a method of describing data that reduces the role of outliers on the measurement of data set's variability?

The grade point averages of students from your high school's honors biology class

Which of the following sets of data is likely to have the smallest standard deviation?

you would never obtain a negative variance

You would obtain a negative value for the variance if...