Stat Test One
What type of variable is the number of auto accidents reported in a given month?
Discrete
The terms descriptive statistics and inferential statistics can be used interchangeably.
False
The variance is the mean of the sum of the squared deviations between each observation and the median
False
There are four levels of measurement-qualitative, quantitative, discrete, and continuous.
False
To convert a frequency distribution to a relative frequency distribution, divide each class frequency by the number of classes.
False
To summarize the gender of students attending a college, the number of classes in a frequency distribution depends on the number of students.
False
For any set of data, which measures of central location have only one value?
Mean and Median
Which measure of central location are not affected by extremely small or extremely large values?
Mode and median
A marketing class of 50 students evaluated the instructor using the following scale: superior, good, average, poor, and inferior. The descriptive summary showed the following survey results: 2% superior, 8% good, 45% average, 45% poor, and 0% inferior.
Most students rated the instructor as poor or average
The names of the positions in a corporation, such as chief operating officer or controller, are examples of what type of variable?
Qualitative
What type of variable is the number of robberies reported in your city?
Quantitative
The Nielsen Ratings break down the number of people watching a particular television show by age. Age is what level of measurement?
Ratio
The incomes of a group of 50 loan applicants are obtained. Which level of measurement is income?
Ratio
Your height and weight are examples of which level of measurement?
Ratio
Monthly commissions of first-year insurance brokers are $1,270, $1,310, $1,680, $1,380, $1,410, $1,570, $1,180 and $1,420. These figures are referred to as:
Raw Data
What is a portion or part of a population called?
Sample
The general process of gathering, organizing, summarizing, analyzing, and interpreting data is called
Statistics
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 class interval, which is the width of a class, can be determined by subtracting the lower limit of a class from the lower limit of the next higher class.
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
The arithmetic mean is the sum of the quantitative observations divided by the total number of observations
True
The arithmetic mean is the sum of the quantitative observations divided by the total number of observations.
True
The average number of passengers on commercial flights between Chicago and New York City is an example of a statistic.
True
The mode is the value of the observation that appears most frequently.
True
The number of children in a family is a discrete variable.
True
The principal difference between the interval and ratio scale is that the ratio scale has a meaningful zero point.
True
The standard deviation is the positive square root of the variance
True
The sum of the deviations from the mean for the set of numbers 4, 9, and 5 will equal zero.
True
When data is collected using a quantitative, ratio variable, what is true about a frequency distribution that summarizes the data?
Upper and lower class limits must be calculated
What is the relationship between the variance and the standard deviation?
Variance is the square of the standard deviation
A student was studying the political party preferences of a university's student population. The survey instrument asked students to identify themselves as a democrat or a republican. This question is flawed because:
the categories are not exhaustive
In a negatively skewed distribution
the mean is smaller than the median
If the variance of the "number of daily parking tickets issued" is 100, the variance is defined as
"number of daily parking tickets issued" squared
The monthly salaries of a sample of 100 employees were rounded to the nearest $10. They ranged from a low of $1,040 to a high of $1,720. If we want to condense the data into seven classes, what is the most convenient class interval?
$100
A group of 100 students was surveyed about their interest in a new International Studies program. Interest was measured in terms of high, medium, or low. 30 students responded high interest; 40 students responded medium interest; 30 students responded low interest. What is the relative frequency of students with high interest?
0.30
Refer to the following information from a frequency distribution for "heights of college women" recorded to the nearest class midpoints are 62.5" and 65.5". What is the class interval?
3"
According to the Empirical Rule, about what percent of the observations are within 2 standard deviations of the mean?
95%
When data is collected using a qualitative, nominal variable, what is true about a frequency distribution that summarizes the data?
A pie chart can be used to summarize the data
A student was interested in the cigarette smoking habits of college students and collected data from an unbiased random sample of students. The data is summarized in the following table: Males who Smoke 20 Males who don't Smoke 30 Females who Smoke 25 Females who don't Smoke 50 What type of chart best represents the frequency table?
Bar Chart
What is a disadvantage of the range as a measure of dispersion?
Based on only two observations
A disadvantage of using an arithmetic mean to summarize a set of data is that the arithmetic mean
Can be biased by one or two extremely small or large values
The performance of personal and business investments is measured as a percentage, "return on investment". What type of variable is "return on investment"?
Continuous
What type of variable is "pounds of popcorn" served at a movie theater?
Continuous
What type of variable is the number of gallons of gasoline pumped by a filling station during the day?
Continuous
A frequency distribution for qualitative data has class limits
False
A listing of 100 family annual incomes is an example of statistics.
False
A store asks shoppers for their zip code to identify market areas. Zip codes are an example of ratio data.
False
According to the Empirical Rule, 75% of the observations lie within plus and minus 2.00 average mean deviations.
False
Categorizing voters as Democrats, Republicans, and Independents is an example of interval level measurement.
False
Descriptive statistics are used to find out something about a population based on a sample.
False
Extremely high or low scores affect the value of the median
False
In a company, the standard deviation of the ages of female employees is six years and the standard deviation of the ages of male employees is ten years. These statistics indicate that the dispersion of age is greater for females than for males
False
The Union of Electrical Workers of America with 9,128 members polled 362 members about a new wage package that will be submitted to management. The population is the 362 members
False
The order that runners finish in a race would be an example of continuous data.
False
The ordinal level of measurement is considered the "lowest" level of measurement
False
What level of measurement is the Centigrade temperature scale?
Interval
The reported unemployment is 5.5% of the population. What measurement scale is used to measure unemployment?
Interval or Ratio
A survey includes a question regarding marital status that has the following responses: single, married, divorced, separated, or widowed. What is the scale of measurement for this question?
Nominal
If Gallup, Harris, and other pollsters asked people to indicate their political party affiliation as Democrat, Republican, or Independent, the data gathered would be an example of which scale of measurement?
Nominal
Shoe style is an example of what level of measurement?
Nominal
The Equal Employment Opportunity Act requires employers to classify their employees by gender and national origin. Which level of measurement is this?
Nominal
The members of each basketball team wear numbers on their jerseys. What scale of measurement are these numbers considered?
Nominal
What level of measurement is a person's "favorite sport"?
Nominal
A bank asks customers to evaluate the drive-thru service as good, average, or poor. Which level of measurement is this classification?
Ordinal
A group of women tried five brands of fingernail polish and ranked them according to preference. What level of measurement is this?
Ordinal
Respondents were asked, "Do you now earn more than or less than you did five years ago?" What is this level of measurement?
Ordinal
The final rankings of the top 20 NCAA college basketball teams are an example of which level of measurement?
Ordinal
What is the lowest level of measurement that a median can compute?
Ordinal
The relative frequency for a class represents the
Percent of observations in the class
A group of 100 students was surveyed about their interest in a new International Studies program. Interest was measured in terms of high, medium, or low. 30 students responded high interest; 40 students responded medium interest; 20 students responded low interest. What is the best way to illustrate the relative frequency of student interest?
Pie Chart
What is the shape of a frequency distribution with an arithmetic mean of 800 pounds, median of 758 pounds, and a mode of 750 pounds?
Positively skewed
Which word is NOT a part of the definition of descriptive statistics?
Predicting
In the calculation of the arithmetic mean for grouped data, which value is used to represent all the values in a particular class?
The class midpoint
A student was interested in the cigarette smoking habits of college students and collected data from an unbiased random sample of students. The data is summarized in the following table: Males 50 Females 75 Males who Smoke 20 Males who don't Smoke 30 Females who Smoke 25 Females who don't Smoke 50 Why is the table NOT a frequency distribution?
The classes are not mutually exclusive
A population is a collection of all individuals, objects, or measurements of interest.
True
An ordinal level of measurement implies some sort of ranking.
True
Data measured on a nominal scale can only be classified into categories
True
Dispersion describes the degree of variation in the data
True
For any data set, Chebyshev's Theorem estimates the proportion of observations that occurs within k standard deviations of the mean, where k is greater than 1.0.
True
In a bar chart, the x-axis is labeled with the values of a qualitative variable.
True
Which of the following is an example of a continuous variable? a. Tons of concrete to complete a parking garage b. Number of students in a statistics class c. Zip codes of shoppers d. Rankings of baseball teams in a league
a. Tons of concrete to complete a parking garage
When TV advertisements report "2 out of 3 dentists surveyed indicated they would recommend Brand X toothpaste to their patients," an informed consumer may question the conclusion because the:
advertisement does not include the total number of dentists surveyed
Which of the following is an example of qualitative variable? a. Number of children in a family b. Weight of a person c. Color of ink in a pen d. Miles between oil changes
c. Color of ink in a pen
Which on of the following is NOT an example of discrete data? a. Number of households watching the Home Shopping Network b. Number of employees reporting in sick c. Number of miles between New York City and Chicago d. Number of members of the Denver Lions Club
c. Number of miles between New York City and Chicago
A purchasing agent for a trucking company is shopping for replacement tires for their trucks from two suppliers. the suppliers' prices are the same. However, Supplier A's tires have an average life of 60,000 miles with a standard deviation of 10,000 miles. Supplier B's tires have an average life of 60,000 miles with a standard deviation of 2,000 miles. Which of the following statements is true? a. The two distributions of tire life are the same b. On average, Supplier A's tires have a longer life then Supplier B's tires c. The life of Suppler B's tire is more predictable than the life of Supplier A's tires d. The dispersion of Supplier A's tire life is less than the dispersion of Supplier B's tire life
c. The life of Suppler B's tire is more predictable than the life of Supplier A's tires
The relative frequency for a class is computed as the class a. width divided by class interval b. midpoint divided by the class frequency c. frequency divided by the class interval d. frequency divided by the total frequency
d. frequency divided by the total frequency
The sum of the deviations from the mean is always
equal to zero