Chapter 12 - Description & Correlation

Brewster measures the height and age of four and five year-olds. To his surprise, he finds no correlation between height and age. What is most likely responsible for his results?

He has restricted the range of the variables.

Which one of the following would be an appropriate measure of central tendency to summarize ordinal data?

Median

Which one of the following is NOT a measure of central tendency?

Meridian

A researcher finds that out of 400 pet owners surveyed, 250 own only a dog, 125 own only a cat, and 25 own only a bird. Which measure of central tendency is the most appropriate for this data?

Mode

Which one of the following scales of measurement lacks numeric properties?

Nominal

Any set of scores may be described by measures of ________ and ________.

central tendency; variability

A teacher writes the results of a test on the board: 7 students received A's, 10 students received B's, 18 students received C's, 4 students received D's, and 1 student received an F. In statistical terms, this is a

frequency distribution.

The correlation coefficient

is a statistic that describes how strongly variables are related to one another.

A host of a home repair program rates the difficulty of various home improvement projects. He assigns the level of difficulty by using hammers: 3 for very difficult, 2 for moderate, and 1 for easy. This measure is an example of a(n) _____ scale.

ordinal

The range and the standard deviation are both (a) measures of variability. (b) descriptive statistics. (c) useful ways to summarize data. (d) All of these

All of these

Henry finds that for automobile owners, as the price of gasoline increases, the amount of miles they drive in a week decreases. This finding would suggest _____ relationship.

a negative

In studying the effect of temperature on ice cream cone sales, a researcher could record the number of ice cream cones sold on cold versus hot days. The researcher would be most interested in

comparing group means.

What is the difference between an interval and a ratio scale? A ratio scale _____ while an interval scales does not.

has an absolute zero

A predictor variable is generally analogous to a(n) ________ variable in the experimental method.

independent

All correlation coefficients

range from -1.00 to +1.00.