Business Stat

When you create a dot plot, you do which of these operations?

"Pile up" dots that are too close to show separately. Place a dot along a horizontal scale for each observation.

A sample of experienced typists revealed that their mean typing speed is 87 words per minute and the median typing speed is 73 words per minute. The standard deviation of typing speed is 16.9 words per minute. What is the Pearson coefficient of skewness?

+2.5

For the following ordered set of data, find the 60th percentile. 0, 2, 3, 5, 5, 6, 8, 10, 10, 11, 12, 14, 16

10

The 67th percentile is

the value below which 67% of the observations occur

In a contingency table, we describe the relationship between

two variables measured at the ordinal or nominal level

The test scores for a class of 147 students are computed. What is the location of the test score associated with the third quartile?

111

Quartiles divide a distribution into

4 equal parts

A dot plot can be used to show

The distribution for a quantitative variable

What is the possible range of values for Pearson's coefficient of skewness?

−3 and +3

The interquartile range is graphically presented in a

box plot

The 25th percentile is referred to as the

first quartile

The eighth decile

is the same as the 80th percentile

In a distribution, the second quartile corresponds with the

median

For the following ordered set of data, find the 90th percentile. 0, 2, 3, 5, 5, 6, 8, 10, 10, 11, 12, 14, 16, 20, 23

21.2 The 90th percentile is 40% of the way from the 14th observation to the 15th observation. 20 + .4(23-20) = 21.2

For the following ordered set of data, find the 25th percentile. 0, 0, 2, 3, 5, 5, 6, 7, 7, 8, 9, 10, 11, 13, 14

3 Reason: L25= (15 + 1) 2510025100 = 4 Locate the fourth value in the ordered array.

In the following set of data: (1, 3, 5, 6, 7, 9, 100), what are the first, second, and third quartiles?

3, 6, 9

Which of the following are features of a dot plot?

Dots "piled up" for observations very close together. One dot for each observation. A horizontal line indicating the possible values of the data.

What does the interquartile range describe?

The range of the middle 50% of the observations

What is the measure of position called below which 75% of the observations occur?

The third quartile

For a given data set, suppose Q1 = 40, Q2 = 45, Q3 = 50. Also, suppose that the three smallest observations are 20, 24, and 28. Which of the following is true about the box plot for this data set?

There would be two asterisks plotted to indicate outliers at 20 and 24.

For the following ordered set of data, find the 40th percentile. 0, 2, 4, 5, 5, 6, 7, 7, 8

5

What would the location of the 11th percentile be for a data set with 50 observations?

5.61

Using the following statistics to describe a distribution of data, what is the interquartile range? Minimum = 10 Q1 = 25 Median = 50 Q3 = 75 Maximum = 95

50

The median of a sample will always equal the

50th percentile

For a given data set, suppose Q1 = 70, Q2 = 80, Q3 = 100. Which of the following is true about outliers?

An observation of 20 would be an outlier.

Choose the correct formula for the location, Lp ,from n observations where P is the desired percentile

Lp =(n+1)(P/100)

Dot plots allow one to observe which of the following?

The center of a distribution. The spread in a distribution. The shape of a distribution.

If a set of data exhibits significant positive skewness, then which of the following would be expected of Pearson's coefficient of skewness?

The coefficient should be close to 3.

Which one of these statements is not part of the description of a scatter diagram?

The data points are connected to create a graph.

The interquartile range is a measure of dispersion usually used along with the median. What is the definition of interquartile range?

The distance between the first and third quartile.

Suppose a given data set has the following characteristics: Minimum value: 120 Q1: 160 Q2: 190 Q3: 200 Maximum Value: 220 Which of the following is true about the distribution of the data?

The distribution is negatively skewed. The distance of the minimum, maximum, Q1, and Q3 from the median provide information about the distribution's skew.

What statements below describe the relative use of dot plots and histograms?

Histograms are more useful for large data sets. Dot plots are most useful for small data sets.

Which of the following is not a measure of position?

standard deviation

Which of the following are measures of position?

the deciles the quartiles the median

Which of the following statements describe a feature of a scatter diagram? Select all that apply.

Each paired observation is represented by a single dot One variable is scaled on the horizontal axis and the other is scaled on the vertical axis

Which one of the following pairs of variables would be best-suited for a contingency table?

Favorite Color and Gender

Choose the statement that best describes a scatter diagram.

A graphical technique to show the relationship between two variables.

A dot plot would be appropriate to display which one of the following kinds of data?

A small set of data.

First Quartile

Separates the bottom 25% of the data from the upper 75%

Second Quartile

Separates the bottom 50% of the data from the upper 50%

Third Quartile

Separates the bottom 75% of the data from the upper 25%

Contingency tables are used for summarizing data of what level? Select all that apply.

Nominal Ordinal