BSTATS Test 1

What type of variable is the number of robberies reported in your city

Discrete

The sum of the deviations form the mean for the set of numbers 3,-9 and 5 will equal one

False

There are four levels of measurement: qualitative, quantitative, discrete, and continuous

False

Which measures of centrla location always have only one value for a set of grouped or ungrouped data

Mean and median

A question in a market survey asks for a respondent's favorite car color. Which measure of central location should be used to summarize this question?

Mode

Which measures of central location are not affected by extremely small or extremely large values?

Mode and median

A small sample of computer operators shows monthly incomes of $1,950, $1,775, $2,060, $1,840, $1,795, $1,890, $1,925 and $1810 What are these ungrouped numbers called?

Raw data

What is a portion of a population called?

Sample

A simple graphical technique for studying the relationship between two variables is

Scatter plot

The main purpose of descriptive statistics is to

Summarize data in a useful and informative manner

What is the relationship among the mean, median and mode in a symmetric distribution

They are all equal

A Pareto chart can be used to differentiate the "vital few" causes of quality problems from the "trivial many" causes of quality problems

True

A box plot shows the relative symmetry of a distribution

True

A cumulative frequency distribution is used when we want to determine how many observations lie above or below certain values.

True

A frequency distribution groups data into classes showing the number of observations in each class

True

A frequency polygon is a very useful graphic technique when comparing two or more distributions

True

A line graph is a graphic that is used to display the changes in a variable over time

True

The principal difference between the interval and ratio scale is that the ratio scale has a meaningful zero point.

True

Three quartiles divide a set of data into four quarters

True

To convert a frequency distribution to a relative frequency distribution, divide each class frequency by the total sum of all class frequencies

True

The closing prices of a common stock have been 61.5, 62, 61.25, 60.875 and 61.5 for the past week. What is the range

$1.125

The net income (in $ millions) of a sample of steel fabricators are: $85, $67, and $85. What is the modal net income?

$85

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

What is the median of 26,30,24,32,32,31,27 and 29

29.5

What is a disadvantage of the range as a measure of dispersion?

Based on only 2 observations

Sometimes, data has two values that have the highest and equal frequencies. In this case, the distribution of the data can best be described as

Bimodal (having two modes)

In a frequency distribution, what is the number of observations in a class called?

Class frequency

The relative frequency for a class is computed as

Class frequency divided by the total frequency

Which of the following is an example of attribute data

Color of ink in a pen

Which can be used to study the relationship between two attributive variables

Contingency table

What type of variable is the number of gallons of gasoline pumped by a filling station during a day?

Continuous

A relative frequency distribution shows the number of observations in each class

False

A set of ordinal, interval or ratio level data may only have one mode

False

Descriptive statistics-is used to make inferences about a population based on a sample, such as the population's average weight

False

For a set of data arranged or sorted in numerical order, the value of the observation in the center is called the weighted mean

False

For a symmetrical distribution, the variance is equal to the standard deviation

False

Ogive plot is a graph used to depict frequency or relative frequency of qualitative data

False

Pie chart is a graphical technique that places quantitative values from smallest to largest and allows us to see the shape of the dataset's distribution

False

The Union of electrical workers of America with 9,128 members polled 5,365 members regarding a new wage package to be submitted to management. The 5,365 members is the population.

False

The number of children in a family is a continuous variable

False

The order that runners finish in a race would be an example of continuous data.

False

What level of measurement are the Centigrade and Fahrenheit temperature scales

Interval

A questionnaire contained a question regarding marital status. The respondent checked single, married, divorced, separated or widowed. What is the scale of measurement for this question?

Nominal

Which of the following is an example of a discrete variable

Number of students in a statistics class

A bank asks customers to evaluate the drive-thru service as good, average, or poor. Which level of measurement is this classification

Ordinal

Stem-and-leaf displays are useful for detecting

Outliers

Which word is NOT part of the definition of descriptive statistics

Predicting

A marketing research agency was hired to test a new DVD player. Consumers rated it outstanding, very good, fair or poor. The level of measurement for this experiment is ordinal

True

A negatively skewed distribution is not symmetrical. The long tail is to the left or in the negative direction

True

A population is a collection of all individuals, objects or measurements of interest.

True

A sample is a portion or part of the the population of interest

True

A value that is typical or representative of the data is referred to as a measure of central location

True

Descriptive statistics is used to find out something about a population based on a sample, such as the population's average weight

True

Dispersion is the degree of variation in the data

True

If a variable is measured at the interval or ration level, all the values are included when computing the mean

True

Scatter plot (or diagram) is a simple graphical technique for studying the relationship between two variables

True

Statistics is defined as a body of techniques used to facilitate the collection, organization, presentation, analysis and interpretation of information for the purpose of making better decisions.

True

A graph is used to depict frequency or relative frequency of qualitative data

pie chart