Exam #1 Business Statistics, BUS 221: Exam 1
Respondents were asked, "Do you now earn more than or less than you did five years ago?" What is this level of measurement?
Ordinal
Which word is NOT a part of the definition of descriptive statistics?
Predicting
how else can you determine the 50th percentile?
Q3-Q1
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
Science of collecting, organizing, presenting analyzing and interpreting numerical data to assist in making more effective decision
Statistic
The main purpose of descriptive statistics is to:
Summarize data in a useful and informative manner.
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 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 population is a collection of all individuals, objects, or measurements of interest.
TRUE
A sample is commonly a fraction of the population
TRUE
If we select 200 persons out of 55,000 club members and ask them about candidates and issues, the 55,000 persons are referred to as the population.
TRUE
The midpoint of a class, which is also called a class mark, is halfway between the lower and upper limits.
TRUE
The number of children in a family is a discrete variable.
TRUE
To construct a histogram, the class frequencies are plotted on the vertical or Y-axis, and either the stated limits, the true limits or the midpoints are plotted on the horizontal or X-axis.
TRUE
To convert a frequency distribution to a relative frequency distribution, divide each class frequency by the sum of the frequencies of all classes.
TRUE
To infer something a population, we usually take a sample from the population.
TRUE
what mean deviation formula means
sum of the (data - mean) for each data and divide by the number of data
variable - GPA
continuous
variable that can be any #
continuous
type of statistic that has exact # and info
descriptive
"gaps" in data
discrete
# of children (variable)
discrete
A measure of location, such as the mean or the median, only describes the center of the data. It is valuable from that standpoint, but it does not tell us anything about the spread of the data
dispersion
separateness
dispersion
stem and leaf plot pro
do not loose value/identity of observation
What does a box plot show?
minimum value, first quartile, median, third quartile, maximum value
mode
most often value
Standard deviation formula mean
sum of all of the data (data-mean)^2 divided by the # of data - 1
# of classes saying
"2 to the k rule"
"2 to the k rule" formula
2^k>n
Calculate class interval
2^k>n i≥(H-L)/k
formula for coefficient variation
CV = s/x`(100%)
A relative frequency distribution shows the number of observations in each class.
FALSE
If we select 100 persons out of 25,000 registered voters and ask them about candidates and issues, the 100 persons are referred to as the population.
FALSE
In constructing a frequency distribution, you should try to have open-ended classes such as "Under $100" and "$1,000 and over".
FALSE
In general, we should construct a frequency distribution so that there are either 4 or 24 classes.
FALSE
The orders that runners finish in a race would be an example of continuous data.
FALSE
The techniques used to find out something about a population, such as their average weight, based on a sample are referred to as descriptive statistics.
FALSE
The word descriptive statistics and inferential statistics can be used interchangeably.
FALSE
When constructing a frequency distribution, try to include overlapping class limits, such as 100 up to 201, 200 up to 301, and 300 up to 401.
FALSE
The branch of statistics that we draw conclusions from about the population, based on sample data is called _________________ statistics.
Inferential
What level of measurement do Centigrade and Fahrenheit temperature scales represent?
Interval
what is the 50th percentile of a distribution?
L50=(# of data - 1)(50/100)
mean deviation formula
MD=∑|x-x`| / n
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.
If Gallup, Harris, and other pollsters asked people to indicate their political party affiliation - Democrat, Republican or Independent, which level of data measurement would the responses represent?
Nominal
The monthly Consumer Price Index is an example of a
statistics
When TV advertisements report that "2 out of 3 dentists surveyed indicated that 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.
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.
how do you determine the mean?
add all data and divide by the # of data give
converting a frequency distribution to relative frequency
class frequency/total # of observations
Relative dispersion of number can also be defined as?
coefficient of variation
ratio of standard deviation to arithmetic mean expressed as a %
coefficient of variation
classify observation according to 2 identifiable characteristics
contingency table
For a symmetrical, bell-shaped frequency distribution, approximately 68 percent of the observations will lie within plus and minus one standard deviation of the mean; about 95 percent of the observations will lie within plus and minus two standard deviations of the mean; and practically all (99.7 percent) will lie within plus and minus three standard deviations of the mean.
empirical rule
what does a relative frequency distribution show?
fraction or % of data values in each class
grouping of quantitative data into classes showing the number of observations in each mutually exclusive class
frequency distribution
how do you find the highest and lowest frequencies of a class?
frequency distribution
what is a cumulative frequency distribution?
frequency table with data, interval, and frequency number added all the way down
relative distribution formula
frequency/total number of observations
Calculate range
highest value - lowest value
type of statistic that is based on samples
inferential statistic
Q3-Q1
interquartile deviation
dress size
interval
temperature
interval
what type of measurement has no natural 0
interval
meaningful amounts of differences between data values can be determined
interval measurement
interval formula
i≥(H-L)/k
what is the negatively skewed distribution?
mean<median<mode
median
middle # of data
Make of cars
nominal
Measurement has categories and cannot be arranged in a particular order
nominal
jersey #
nominal
m&m colors
nominal
Geometric mean formula
n√(x1)(x2)...
The level of measurement of a teacher like this .... superior, very good, average, poor is
ordinal
data arranged in some order but the differences between data values cannot be determined
ordinal
team standings
ordinal
gender, religion, eye color
qualitative variable
variable characteristic being studied is non numerical
qualitative/attribute variable
variable - info reported numerically
quantitative variable
examples of dispersion
range, mean deviation, variance and standard deviation
distance to class
ratio
# of patients seen
ration
interval level with 0 starting point
ration
unanalyzed data
raw data
what do you need to commute the mean?
raw data
when is a cumulative frequency distribution show?
running total of how many times something happens
coefficient of variation formula
s/x`(100%)
what formula for standard deviation
s=√[(data1-mean)^2/# of classes - 1]+[(data2-mean)^2/# of classes - 1]....
formula for standard deviation
s=√∑(x-x`)^2/n-1
portion, part of population of interest
sample
what is the meaning of the height of a histogram bar?
size of class or class frequency
skeness formula
sk=3(x` - median)/s
midpoint of a class
upper limit+lower limit/2
The principal difference between the interval and ratio scale of measurement is that the ratio scale has a meaningful
zero point
Standard deviation formula
√∑(x-x`)^2 / n-1
what is s formula?
√∑(x-x`)^2 / n-1