BUSN Stats Exam 1

The formulas are functionally the same, but 'n' (the sample size) is used instead of 'N' (the population size).

How does the formula for the sample mean differ from the formula for population mean?

class midpoints

In a frequency polygon the points are plotted at the intersection of the class frequencies and the:

k is the smallest number of classes such that 2k is greater than the number of observations.

In using the "2 to the k rule" to determine the number of classes for a frequency distribution, what is the meaning of the variable k?

A symmetrical distribution.

The mean, median, and mode are all the same for which type of distribution?

Inferential Statistics

The methods used to estimate a property of a population on the basis of a sample

Nominal, Ordinal, Interval, and Ratio

The mode can be computed for which of the following levels of data?

Observations of a qualitative variable that can only be classified and counted.

The nominal level of data describes what type of information?

Excluding outliers that cause the interval to be too wide.

Which of the following is not a useful practice in setting individual class limits for a frequency distribution?

Halfway between the lower or upper limits of two consecutive classes.

Which of the following is the best definition of "class midpoint"?

All of the automobiles sold in Canada in 2016.

Which of the following is the best definition of a statistical population?

Medians can be calculated from ordinal-level data, but means can't.

Which of the following is true regarding medians and means?

- Ordinal level data - Ratio level data - Interval level data

Which of the following kinds of data can be used to find a median value?

-Ordinal level data - Ratio level data -Interval level data

Which of the following kinds of data can be used to find a median value?

The relative frequency is found by dividing the class frequencies by the total number of observations.

Which of the following operations is true regarding relative frequency distributions?

Brand of newly purchased TV.

Which of the following represents data recorded at the nominal level?

-It is used when there are several observations of the same value. -The denominator of the weighted mean is always the sum of the weights. -It is a special case of the arithmetic mean.

Which of the following statements are true of the weighted mean? Select all that apply.

It summarizes qualitative data.

Which one of the following is not a characteristic of a frequency distribution?

A small number of observations are much larger in value than most of the data.

Which one of the following is true for a positively skewed distribution?

Only the mode can be used for nominal-level data.

Which one of the following is true regarding the use of the mode, mean, and median for different levels of measurement?

The number 23 is much larger than the other numbers and would unduly influence the mean.

Why would the median be a better measure of the center than the mean for the following set of data? 3, 4, 4, 4, 5, 6, 7, 23

statistic

a characteristic of a sample

median

the midpoint of the values after they have been ordered from the minimum to the maximum values

mode

the value of the observation that appears most frequently

Quantitative variable

when a variable can be reported numerically

qualitative variable or an attribute

when an object or individual is observed and recorded as a nonnumeric characteristic, it is... - Ex. gender, beverage preference , type of vehicle owned, state of birth, and eye color

Interval level of measurement

- For data recorded at the interval level of measurement, the interval or the distance between values is meaningful. The interval level of measurement is based on a scale with a known unit of measurement

Discrete Quantitative variables

- can assume only certain values, and there are "gaps" between the values

Descriptive Statisitcs

- methods of organizing, summarizing, and presenting data in an informative way - masses of unorganized data - Ex. census of population, weekly earning of thousands of computer programmers

Statitics

-the science of collecting, organizing, presenting, analyzing, and interpreting data to assist in making more effective decisions - about collecting and processing information to create a conversation, to stimulate additional questions, and to provide a basis for making decisions

1. data are collected everywhere and require statistical knowledge to make information useful 2. statistical techniques are used to make professional and personal decisions 3. no matter what career, you will need a knowledge of statistics to understand the world and be conversant in your career

3 reasons for studying statistics

a histogram

A frequency polygon shows the shape of a distribution and is similar to:

A relative frequency distribution shows:

A relative frequency distribution shows:

the fraction or percentage of observations in each class interval

A relative frequency distribution shows:

continuous quantitative variable

Can assume any value within a specific range. Ex. air pressure in tires and the weight of a shipment of tomatoes

Bar Chart

Observations of a qualitative variable that can only be classified and counted.

Histogram

Observations of a qualitative variable that can only be classified and counted.

Pie Chart

Observations of a qualitative variable that can only be classified and counted.

frequency distribution

Observations of a qualitative variable that can only be classified and counted.

frequency polygon

Observations of a qualitative variable that can only be classified and counted.

frequency table

Observations of a qualitative variable that can only be classified and counted.

Ferequency

The number of observations in each class is called the class ______.

counting the number of observations less than the upper limit of the class.

The value shown on the vertical axis of a cumulative frequency polygon for a particular class is found by:

When the data set includes one or two very large or very small values.

What characteristic of a data set makes the median the better measure of the center of the data than the mean?

The qualitative class labels.

What information is shown on the horizontal axis of a bar chart?

Ratio

Which level of data gives the most information about the observation?

-There are gaps between the values of this variable. -It can be used to count items. -It can assume only certain values within a range.

Which of the following are attributes of a discrete quantitative variable? Choose all that apply.

-For many sets of data there is no mode. - For many sets of data there are multiple modes.

Which of the following are disadvantages of the mode?

The distance between values is a known unit of measure.

Which of the following best describes interval-level data?

-Classes -Class frequencies - The shape of the distribution

Which of the following can be observed from a histogram?

The frequency of occurrence of a nominal variable.

Which of the following features is not part of a histogram?

It allows comparing directly two or more frequency distributions.

Which of the following is an advantage of a frequency polygon over a histogram?

mean

counting the number of observations less than the upper limit of the class.

parameter

counting the number of observations less than the upper limit of the class.

population mean

counting the number of observations less than the upper limit of the class.

Nominal level of measurement

data recorded at the nominal level of measurement is represented as labels or names. They have no order. They can only be classified and counted

Ordinal Level of Measurement

data recorded at the ordinal level of measurement is based on a relative ranking or rating of items based on a defined attribute or qualitative variable. Variables based on this level of measurement are only ranked or counted

Ratio level of measurement

data recorded at the ratio level of measurement are based on a scale with a known unit of measurement and a meaningful interpretation of zero on the scale.

levels of measurement

determines how data should be summarized and presented - nominal - ordinal - interval - ratio

sum of all values in the population / number of values in the population

formula for population mean

sum of all the values in a sample / number of values in the sample

formula for sample mean

- to compute a mean, the data must be measured at the interval or ratio level - all values are included in calculating the mean - the mean is unique -the sum of all deviations of each value from the mean is zero

properties of the arithmetic mean

- it is not affected by extremely large or small numbers - It can be computed for ordinal level data or higher

properties of the median

1. decide on the number of classes 2. determine the class interval 3. set the individual class limits 4. tally the vehicle profit into the classes and determine the number of observations in each class

steps to make a frequency distribution