Frequency Distributions, Relative Frequencies, Proportions, and Two-Way Tables (Notes Review)

Flashcards covering sample vs population, proportions, relative frequencies, frequency distributions, and two-way tables from the notes.

For the paying job survey data, what constitutes the sample?

5204 first-year, full-time college students.

Concerning the paying job survey data, what is the population of interest?

College students (the intended population).

Using the paying job survey data, how is the proportion of students without a paying job calculated?

2649 / 5204 = 0.509 (three decimals).

Using the paying job survey data, how is the proportion of students with a paying job (on or off campus) calculated?

(1436 + 1119) / 5204

\approx 0.491.

Define relative frequency.

The proportion of observations for a specific category, found by dividing the category's frequency by the total number of observations.

Relative frequency is the same as which other measure?

A proportion.

How can relative frequencies be represented?

As a fraction or a decimal.

How do you convert a relative frequency to a percentage?

Multiply by 100%.

How do you convert a percentage to a relative frequency?

Divide the percentage by 100%.

What should the sum of all relative frequencies be?

1.

Given a dataset of size 300 where a class has a relative frequency of 0.30, what is its frequency?

90.

In the provided partial table, what is the relative frequency of class D?

0.30.

Referring to that partial table, what is the frequency of class D?

90.

What is a frequency distribution?

A tabular summary that displays the frequency of observations within distinct, non-overlapping categories.

What does the total frequency equal for a sample?

The sample size, n.

What does the total frequency equal for a population?

The population size, N.

Why organize quantitative data into classes when creating a frequency distribution?

To create a grouped frequency distribution by using non-overlapping intervals.

In the smoking cessation study, what were the two groups?

Reward and Deposit.

In that study, how many participants quit in the Reward group?

156.

In the Deposit group, how many participants quit?

78.

How many participants were assigned to the Deposit group?

146.

What is the total number of participants in the study?

1060.

What is the proportion of participants assigned to the Deposit group?

146 / 1060 = 0.138 (13.8%).

What is the quit success rate in the Reward group?

156 / 914 = 0.171 (17.1%).

What is the quit success rate in the Deposit group?

78 / 146 = 0.534 (53.4%).

What are the two variables in the smoking cessation two-way table?

Group (Reward vs Deposit) and Quit status (Quit vs Not Quit).

What is the total number of participants in the Reward group?

914.

What is the total number of participants in the Deposit group?

146.

What is the total number of quitters across both groups?

234.

What is the total number not quitting across both groups?

826.

What is the sum of all frequencies in a frequency distribution?

The total frequency.

If data come from a sample, what is the relationship between total frequency and sample size?

Total frequency equals the sample size n.

If data come from a population, what is the relationship between total frequency and population size?

Total frequency equals the population size N.

What is a key purpose of a frequency distribution?

To summarize data in categories or classes.

For the given partial frequency distribution specific to students, what is the total sample size

Total sample size in that example is 20.