Exam 3: Descriptive Study of Bivariate Data

Usually, the predictor or ______ variable is denoted by the letter ______.

An experimental study of the relation between two variables is often motivated by a need to predict one from the other. The first step in such a study is to plot and examine the scatter diagram.

The numerical value of r indicates how effectively y can be predicted from x.

Find the least squares fitted line when the values of y and x are

Observations on two or more variables recorded for the individual sampling units are called ______ or multivariate data.

Final grades of students enrolled in an Introductory Statistics course are summarized below. Complete the following table by calculating the relative frequencies separately for each row. Round your answers to three decimal places.

In a group of 280 college students, 55 are science majors, 86 are freshmen, and 50 are both. Based on these data, calculate the relative frequencies.

The false correlation produced by a lurking variable is called ________ correlation.

Final grades of students enrolled in a Introductory Statistics course are summarized below. Calculate the remaining marginal totals.

A survey was conducted to study the degree of satisfaction with the service of passengers from New York City to Washington D.C. The following table shows the relative frequencies. Complete the table of cross-tabulated frequencies.

The value of the correlation coefficient r, is always between -1 and ______.

The total frequency for any row is given in the bottom margin.

In an experiment to study the relation between the speed of an athlete running 100 meters, y (meters/second) and the environment temperature, x (Celsius degrees), her trainer collected the following statistics: Find the equation of the least squares fitted line.

In statistical terminology, contingency tables correspond to cross-classified or cross-tabulated data.

In the following instance, would you expect a positive, negative, or zero correlation? The size of an apartment and the sex of the tenant.

What is the graph of the line .

The magnitude of the correlation coefficient r, indicates the strength of a linear relation.

Find the least square fitted line when the values of y and x are

Given the following table of relative frequencies by row, complete the table of cross-tabulated frequencies.

A fabric manufacturer has determined that the resistance y of a fiber is given by y = 18x - 155 where x (in grams) denotes the amount of a synthetic compound used to make the fiber. A) If 44 grams of the synthetic compound are used, what is the resistance? B) At least how many grams of synthetic compound must be used to have a positive resistance?