Deck 4: Numerical Methods for Describing Data

Question 1

If there are no outliers, a skeletal and modified boxplot can differ in the length of the box, but not in the whisker lengths.

Answer 1

False

Question 2

The mean is the middle value of an ordered data set.

Answer 2

False

Question 3

The variance is the positive square root of the standard deviation.

Answer 3

False

Question 4

The trimmed mean is less sensitive to outliers than is the mean.

Question 5

Question 6

An insurance agent is studying fire damage claims in a major city to see if the insurance premiums are matched to the company's risk.She takes a random sample of 20 claims, and finds the amount of each claim, in thousands of dollars.Her results are shown below:

Question 7

In recent years there has been considerable discussion about the appropriateness of the body shapes and proportions of Ken and Barbie dolls.These dolls are very popular, and there is some concern that the dolls may be viewed as having the "ideal body shape," potentially leading young children to risk anorexia in pursuit of that ideal.Researchers investigating the dolls' body shapes scaled Ken and Barbie up to a common height of 170.18 cm (5' 7")and compared them to body measurements of active adults.Common measures of body shape are the chest (bust), waist, and hip circumferences.These measurements for Ken and Barbie and their reference groups are presented in the table below:

Question 8

A wide variety of oak trees grow in the United States.In one locations, and their volumes, in cm3, were recorded.In the table at right are summary statistics for these data. study a sample of acorns was collected from different

Question 9

Consider a study in which the heights of a sample of 1000 high school seniors were recorded.The mean height is 70" and the standard deviation of the heights is 3".It is observed that the height distribution is approximately normal.

Question 10

According to Chebyshev's rule, the fraction of observations that are within 3 standard deviations of the mean is at least eight-ninths.

Question 11

One disadvantage of using the mean as a measure of center for a data set is that its value is affected by the presence of even a single outlier in the data set.

Question 12

The data in the table at right are from observations taken on Historians believe that different mints might reveal themselves in different trace element profiles in the coins; these coins are known to have been minted in Rome.The technique of Atomic Absorption Spectrometry was used to estimate the % by weight of various elements in these coins; the % by weight that is gold is presented here. Roman coins dating from the first three centuries AD. the coins minted in Rome.Some of the summary statistics are given in the table at right.

Question 13

For any given data set, the median must be greater than or equal to the lower quartile, and less than or equal to the upper quartile.

Question 14

The interquartile range is resistant to the effect of outliers.

Question 15

Astronomers are interested in the recessional velocity of

Question 16

By definition, an outlier is "extreme" if it is more than 3.0 iqr away from the closest quartile.

Question 17

When the histogram of a data set is closely approximated by a normal curve, the standard deviation and the interquartile range are very close to equal on average.

Question 18

The % by weight of the element Lead was also calculated for

Question 19

When using a 20% trimmed mean, the largest 10% and the smallest 10% of the observations are discarded for calculation purposes.

Question 20

The % by weight of the element Antimony was also calculated for the coins from a mint in Rome.

Question 21