Exam #1 Business Statistics, BUS 221: Exam 1

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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


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