Chapter 1: Statistics and Data

samples:

a subset of the population

properties of ratio level data:

-Scaled according to amount of characteristic they possess -Equal differences in characteristic = equal differences in measurements -Zero point = absence of characteristic

how do you use stats correctly?

1. find the right data 2. use the appropriate statistical tools 3. clearly communicate the numerical information into written language (interpreting the data)

• Q3: What time should the main dining area close? the above question is which scale of measurement?

Clock time responses are on an interval scale. With this type of data we can calculate meaningful differences, however, there is no apparent zero point.

when fractions have no meaning, which type of variable are you looking at?

qualitative

what are the two types of variables?

quantitative and qualitative

• Q4: How much of your own money did you spend at the lodge today? the above question is which scale of measurement?

Since the tweens' responses are in dollar amounts, this is ratio-scaled data; ratio-scaled data has a natural zero point which allows the calculation of ratios.

population:

consists of all items of interest

this example is a type of what kind of variable? Weight, height, investment return

continuous

which type of variable assumes an infinite number of values within some interval?

continuous

which type of data allows you to look at one point in time to make a comparison (apples-to-apples)

cross-sectional

what are the two types of data?

cross-sectional and time series

this example is a type of what kind of data? data detailing the number of building permits issued in June 2011 in each of the counties of Ohio

cross-sectional data

the nominal scale:

data are simply categories for grouping the data -the least sophisticated -qualitative values may be converted to quantitative values for analysis purposes -nonnumeric label, but a numeric code could be used

what are the two branches of statistics?

descriptive and inferential

this example is a type of what kind of variable? Number of children in a family, number of points scored in a basketball game

discrete

which type of variable assumes a countable number of distinct values?

discrete

what two types of quantitative data are there?

discrete and continuous

inferential statistics:

drawing conclusions about a population based on sample data from that population

variable:

general characteristic being observed

the following examples are for which scale of measurement? Example: Melissa has an SAT score of 1205, while Kevin has an SAT score of 1090. Melissa scored 115 points higher than Kevin Other examples: Temperature readings on a thermometer, scores on USC advanced placement tests

interval

which scale of measurement does this describe? Data may be categorized and ranked with respect to some characteristic or trait.

interval

which scale of measurement does this describe? • Differences between interval values are equal and meaningful. Thus the arithmetic operations of addition and subtraction are meaningful.

interval

which scale of measurement does this describe? • No "absolute 0" or starting point defined. Meaningful ratios may not be obtained.

interval

what are the two types of scales of measurement for quantitative data?

interval and ratio

what is a sample stat?

it's calculated from the sample and is used to make inferences about the population parameter.

the ordinal scale:

may be categorized and ranked with respect to some characteristic or trait -Differences between categories are meaningless because the actual numbers used may be arbitrary

exhaustive:

must appear in one category

what are the two types of scales of measurement for qualitative data?

nominal and ordinal

• Q1: Which radio station was playing on your drive to the ski resort? the above question is which scale of measurement?

nominal data—the values in the data differ merely in name or label.

mutually exclusive:

only fit in one category

"instructors are often evaluated on an ordinal scale (excellent, good, fair, poor)" is an example of which scale?

ordinal

• Q2: Rate the quality of the food at the resort on a scale of 1 to 4. the above question is which scale of measurement?

ordinal since they can be both categorized and ranked.

General Examples: Weight, Time, and Distance Business Examples: Sales, Profits, and Inventory Levels Example: Melissa's college record shows 36 credit hours earned, while Kevin's record shows 72 credit hours earned. Kevin has twice as many credit hours earned as Melissa. Other examples: Miles traveled, monthly incomes, weight of a cut of meat, pressure in an automobile tire the above variable are measured on which scale?

ratio

which scale of measurement does this describe? Differences between interval values are equal and meaningful.

ratio

which scale of measurement does this describe? The strongest level of measurement

ratio

which scale of measurement does this describe? There is an "absolute 0" or defined starting point. "0"does mean "the absence of ..." Thus, meaningful ratios may be obtained.

ratio

which scale of measurement does this describe? data may be categorized and ranked

ratio

what are used to make inferences about a population?

sample statistics

think about the interval or margin between the two things being compared when using which scale of measurement?

the interval scale

statistics:

the methodology of extracting useful information from a data set

which scale of measurement is the most significant?

the ratio scale

descriptive statistics:

the summary of important aspects of a data set by collecting, organizing and then presenting the data

this example is a type of what kind of data? data detailing the number of building permits issued in Lucas County, Ohio in each of the last 36 months

time-series data