Exam 3: Finding Relationships Among Variables

Of those in the sample who did well in the final exam, what percentage of them spent the weekend before the exam studying?

We must specify appropriate bins for side-by-side histograms in order to make fair comparisons of distributions by category.

Displaying all correlations between 0.6 and 0.999 on a scatterplot as green and all correlations between -1.0 and -0.6 as red is known as:

Suppose a car dealer collects the following information about a sample of 448 residents in the city of ABC: · Exact salaries of these ABC residents · Education level (completed high school only or completed college) · Income level (low or high) · Car finance (whether or not the last purchased car was financed) Using the education level, income level, and car finance data, the car dealer creates the three pivot tables shown below. Based on these tables, determine how education and income influence the likelihood that a family finances a car.

A recent survey collected data from 1000 randomly selected Internet users. The characteristics of the users include their gender, age, education, marital status, and annual income. Using Excel^®, the following pivot tables are produced. ​ -Approximate the percentage of these Internet users who are single with no formal education beyond high school.

Do these data help to confirm or contradict the hypothesis that increased wage inequality is associated with lower unemployment levels? [Hint: construct a scatterplot.]

An economic development researcher wants to understand the relationship between the average monthly expenditure on utilities for households in a particular middle-class neighborhood and each of the following household variables: family size, approximate location of the household within the neighborhood, and indication of whether those surveyed owned or rented their home, gross annual income of the first household wage earner, gross annual income of the second household wage earner (if applicable), size of the monthly home mortgage or rent payment, and the total indebtedness (excluding the value of a home mortgage) of the household. The correlation for each pairing of variables are shown in the table below: Table of correlations -Which of the variables have a negative linear relationship with the household's average monthly expenditure on utilities?

Of those in the sample who went partying the weekend before the final exam, what percentage of them did poorly in the exam?

What other data would you need to be more confident that increased income inequality leads to lower unemployment?

A sample of 150 students at a state university was taken after the final business statistics exam to ask them whether they went partying the weekend before the final or spent the weekend studying, and whether they did well or poorly on the final. The following table contains the result. -Of those in the sample who did well on the final exam, what percentage of them went partying the weekend before the exam?

Correlation is a single-number summary of a scatterplot.

The advantage that correlation has over covariance is that the former has a set lower and upper limit.

Scatterplots are also referred to as:

To form a scatterplot of X versus Y, X and Y must be paired variables.

Which Excel^® function allows you to count using more than one criterion?

A recent survey collected data from 1000 randomly selected Internet users. The characteristics of the users include their gender, age, education, marital status, and annual income. Using Excel^®, the following pivot tables are produced. ​ -Approximate the percentage of these Internet users who are currently employed.

Below you will find current annual salary data and related information for 30 employees at Gamma Technologies, Inc. These data include each selected employees gender (1 for female; 0 for male), age, number of years of relevant work experience prior to employment at Gamma, number of years of employment at Gamma, the number of years of post-secondary education, and annual salary. The tables of correlations and covariances are presented below. Table of Correlations Table of Covariances (variances on the diagonal) -Which two variables have the strongest linear relationship with annual salary?

Correlation and covariance measure:

The correlation between two variables is unitless and always between -1 and +1.

If the sample is a good representation of the population, what percentage of those who did poorly on the final exam should we expect to have spent the weekend studying?