QUIZ #1, 302, Fall 99 WITH ANSWERS MARKED

**Please bubble in answers to the first five questions on the group scantron**

1. Social scientists use frequency tables, histograms, or frequency polygons to demonstrate

a. the conclusions they draw from the numbers they collect.

b. the reasoning behind experiments.

c. hypotheses.

**d. how the numbers they collect are distributed.

2. In a histogram, the horizontal (across) dimension represents

**a. possible values the variable can take.

b. intensity of the variable.

c. mean score.

d. frequency.

3. The median is greater than the mean in a distribution that is

a. symmetrical.

b. positively skewed.

c. normal.

**d. negatively skewed.

4. A professor gives an exam in an introductory statistics class and after making a frequency distribution discovers that most students got a perfect score. This is an example of a

a. symmetrical distribution.

b. positively skewed distribution.

**c. ceiling effect.

d. both b and c.

5. If the variance of a set of scores is 9, what is the standard deviation of that set of scores?

a. 18

b. 81

**c. 3

d. 4.5

**Write answers to next questions on this sheet. Please write neatly. Be sure to consult
all group members before writing your answers.**

6. The variance of a group of scores is the average of the

__*Squared deviations from the mean*______________________.

7. If a raw score is 28 and __M __= 20, __SD __= 2, then the __Z __score is ___4___. Show how
you got your answer.

*Z=(X-M)/SD (28-20)/2 = 8/2 = 4 *

*or shown worked out graphically with the number line*

8. What is a parameter?

*A number (or index) that summarizes a feature of a POPULATION distribution *

Give two examples of parameters that statisticians frequently use

_________________ ______________________

*Mean , Variance, Standard Deviation, Skew, Kurtosi*s

(Any two)