Business statistics Chapter 4

Which of the following is true regarding dot plots and histograms?

Dot plots do not lose the identity of individual observations.

Which of the following are features of a dot plot?

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

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

Favorite Color and Gender

Which one of the following is the correct formula to standardize a value?

(Original value - mean)/standard deviation

A large oil company is studying the number of gallons of gasoline purchased per customer at self service pumps. The main number of gallons is 10.0 with a standard deviation of 3 gallons. The median is 10.75 gallons what is Pearson's coefficient of skewness in this instance?

-0.75. Computed by 3(10.0-10.75)/3.0=-0.75

Match the proportion of observations below the measure to the measure of position

1/2 - median 4/5 - 8th decile 3/4 - 3rd quartile 1/5 - 20tg percentile

What would be the location of the 83rd percentile be for a data set with 40 observations?

33.20. Reason: (40+1)(83/100)=34.03

A box plot is best applied when ____

A single variable is summarized

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

The data points are connected to create a graph.

Supposed to given data that has the fallen 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

A dot plot shows the ___

The general shape of a distribution

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

Quartile (Definition)

Values of an ordered, minimum to maximum, data said that divide the data into four intervals

Deciles (definition)

Values of an ordered, minimum to maximum, data that divide the data into 10 equal parts

Percentiles (Definition)

Values of an ordered, minimum to maximum, data that divide the data into 100 intervals

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

a small set of data

Outliers are clearly presented in a _____________.

box plot

The interquartile range is graphically presented in a ____

box plot

Contingency tables are used for summarizing data of what level?

ordinal and nominal

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.

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 interquartile range is the distance between the first and third quartile or 75 - 25 = 50

Choose a statement that best describes a scatter diagram

A graphical technique to show the relationship between two variables.

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

Lp= (n+1)P/100

First quartile definition

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

Second quartile definition

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

Third quartile definition

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

To ____ the data, one should rescale each type of data so that it measures the number of standard deviation above or below the mean for a standard normal distribution

Standardize

If Pearson's coefficient of skewness is equal to zero, the shape of the distribution is

Symmetric. Explanation: based on Pearson's formula, the Souness is equal to zero when the main and median are equal. Using the software coefficient of skew, the coefficient will be zero when the data is perfectly symmetric.

Ways to measure position in a data set

The quartiles, the deciles, the median

Each of the following is a measure of position in a data set except:

The standard deviation

A box plot is constructed using several different values. Which of the following values are included in a box plot

the second quartile, the third quartile, the smallest value

The 75th percentile is referred to as the ____ quartile

third

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

5.61

A dot plot is best applied for a data set with ____

50 observations. Explanation: dot plots are most useful for smaller data sets, whereas histograms tend to be most useful for large data sets.

Forgiven 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

The range of the software coefficient of skewness is ____:

Both positive and negative values

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

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