Social Statistics: Chapter 2

If you have the proportion but need the frequency you just work backwards:

F = P(N)

A frequency distribution...

Is a table reporting the number of observations falling into each category of the variable.

A proportion is really the same as a...

percentage.

Rates are often expressed as...

rates per thousand to eliminate the decimal points and make the number easier to interpret. So you multiply the rate by 1000.

Proportions and percentages are...

relative frequencies

Proportions

should always sum 1.00

Cumulative Distributions

shows the frequencies at or below each category of the variable.

Frequency Distributions

the most basic method for organizing data.

N:

total number of cases

Cumulative distributions are appropriate only for...

variables that are measured at an ordinal level or higher.

A percentage distribution is a table like a frequency distribution but...

with the percentages not the frequencies for each variable.

Percentage (%)

= F/N(100)

Frequency Distributions for Ordinal Variables:

Because the categories or values of ordinal variables are rank- ordered, they must be listed in a way that reflects their rank - from the lowest to the highest or from the highest to the lowest.

A proportion is a relative frequency that is obtained by dividing the frequency in each category by the total number of cases.

P = F/N

If you have the proportion just multiply by 100 to get the percent.

Percentage = P (100)

Rate:

R = AO / PO

Using raw frequency is not very meaningful so we use proportion and percentages...

We call this "relative frequencies".

Cumulative frequency distribution:

a distribution showing the frequency at or below each category (class interval or score) of the variable.

Cumulative percentage distribution:

a distribution showing the percentage at or below each category (class interval or score) of the variable.

Percentage (%):

a relative frequency obtained by dividing the frequency in each category by the total number of cases and multiplying by 100.

Proportion (P):

a relative frequency obtained by dividing the frequency in each category by the total number of cases.

Percentages are relative frequencies that are obtained by...

dividing the frequency in each category by the total number of cases and then multiplying by 100.

A rate is a number obtained by...

dividing the number of actual occurrences in a given time period by the number of possible occurrences.

Frequency Distributions for Interval-Ratio variables:

have a wide range of values, which makes simple frequency distribution very difficult to read simply because there are too many categories.