Exam 2: Descriptive Statistics: Tabular and Graphical Methods

If there are 130 values in a data set,how many classes should be created for a frequency histogram?

When constructing any graphical display that utilizes categorical data,classes that have frequencies of 5 percent or less are usually combined together into a single category.

Leaves on a stem-and-leaf display should be rearranged so that they are in increasing order from left to right.

______________ and _____________ are used to describe qualitative (categorical)data.

The number of weekly sales calls by a sample of 25 pharmaceutical salespersons is below. 24,56,43,35,37,27,29,44,34,28,33,28,46,31,38,41,48,38,27,29,37,33,31,40,50 How many classes should be used in the construction of a histogram?

At the end of their final exam,550 students answered an additional question in which they rated their instructor's teaching effectiveness,with the following results. $\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\text { Student's Rating of Instructor }$ Student's Final Grade Very or Somewhat Effective Very or Somewhat Ineffective A 190 85 B 75 120 C 20 17 D 9 18 F 1 15 What proportion of all 550 students received less than a C?

When data are qualitative,the bars should never be separated by gaps.

The following table lists the types of customer complaint calls on satellite TV service during the first two months after installation.

The number of measurements falling within a class interval is called the ___________.

The stem-and-leaf display is advantageous because it allows us to actually see the measurements in the data set.

The relative frequency is the frequency of a class divided by the total number of measurements.

Row or column percentages can be found in

When developing a frequency distribution,the class (group)intervals should be ___________.

The number of items rejected daily by a manufacturer because of defects for the last 30 days are: 20,21,8,17,22,19,18,19,14,17,11,6,21,25,4,19,9,12,16,16,10,28,24,6,21,20,25,5,17,8 Construct a stem-and-leaf plot.

All of the following are used to describe qualitative data except the ___________.

A CFO is looking at how much of a company's resources are spent on computing.He samples companies in the pharmaceutical industry and develops the following stem-and-leaf graph. 5 269 6 255568999 7 11224557789 8 001222458 9 02455679 10 1556 11 137 12 13 255 What would be the class length used in creating a frequency histogram?

When we wish to summarize the proportion (or fraction)of items in a class,we use the frequency distribution for each class.

The following is a relative frequency distribution of grades in an introductory statistics course.

Recently an advertising company called 200 people and asked them to identify the company that was in an ad running nationwide.The following results were obtained. Female Male Total Correctly recalled the company 66 50 116 Incorrectly recalled the company 44 40 84 Total 110 90 200 What percentage of those surveyed could not correctly recall the company?

A local electronics retailer recently conducted a study on purchasers of large screen televisions.The study recorded the type of television and the credit account balance of the customer at the time of purchase.They obtained the following results. Credit Balance Standard TV LCD Plasma Projection Under \2 00 10 16 40 5 \ 200-\ 800 8 12 24 15 Over \8 00 16 12 16 30 Total 34 40 80 50 What percentage of purchases were plasma televisions by customers with the smallest credit balances?