Quiz

DSRT 734

Test – Residency Section Fall 2020

Instructor: Charles Edeki

Student Name:

Multiple Choice (2 points each) Total points is 50.

1.

Which of the following was listed as a requirement for a fairly complete understanding of a distribution?

a. Variability b. Weight c. Normality d. All of the other alternatives

2.

For a negatively skewed curve, the usual case with continuous data is that

a. high scores are more frequent than low scores and the mean is greater than the median; b. low scores are more frequent than high scores and the mean is greater than the median; c. high scores are more frequent than low scores and the median is greater than the mean; d. low scores are more frequent than high scores and the median is greater than the mean.

3.

“For our study of driving habits, we recorded the speed of every fifth vehicle on Drury Lane. Nearly

every car traveled right at the speed limit or a little over, but there were some that were 10 mph

under, even fewer at 20 mph under, and one car that crept by at just 15 mph. On the basis of the

central tendency calculation on our data, we drew conclusions about all drivers on this stretch of

road.” The proper central tendency value calculated from the data is the

a. population median; b. sample median;

c. population mean ();

d. sample mean (  ).

4.

Which of the following statements is false, according to your text?

a. The salaries of people in sales are more variable than those in management.

b. For a distribution of scores, ŝ is smaller than S. c. Males are more variable than females in reaching puberty. d. none of the other alternatives are correct.

5.

The advantage of using z scores over using raw scores is that z scores allow you to

a. compare a score in one distribution to a score in another; b. understand the relationship of a score to the mean; c. both of the descriptive alternatives; d. neither of the descriptive alternatives.

6.

The standard deviation of the IQ's of students at a high school for the gifted and talented is the

standard deviation of the IQ's of students at a high school, that accepts everyone in its district.

a. less than; b. greater than; c. equal to.

7.

If the standard deviation of a distribution is less than one, the variance will be ________ than the

standard deviation.

a. larger; b. smaller; c. could be either larger or smaller; d. the same size.

Solve the following Problems (12 points Each)

1.

For each study below name the dependent variable, independent variable, and its levels.

a. Thirty females were divided into three equal groups. One group was taught how to concentrate on their breathing. A second group was told to imagine that the day was very hot and that they would be allowed to place their hand in cool water. The third group was

told nothing. All three groups placed their right hand in buckets of ice water for one minute.

Afterward, they rated their pain on a scale of one to seven. b. During Rapid Eye Movement (REM) sleep, muscle tone is lost. For a rat sleeping on a 22-

inch diameter platform over water, REM sleep is interrupted by falling into the water. With

this technique you can deprive rats of REM sleep. Two groups of rats were deprived of

REM sleep for zero or 72 hours. Afterward they learned to choose one arm of a T maze for food reinforcement. Each rat was given 30 trials in the T maze and its percentage of correct

responses was calculated.

c. Four groups of males were monitored during their sleep one night for the number of minutes of Rapid Eye Movement (REM). During the seven hours before sleep one group had seen six

hours of TV, one had seen four hours, one had seen two hours, and one group had seen no

TV.

2.

Describe what each of the following graphs is used for.

a. line graph b. frequency polygon c. histogram d. bar graph

3.

Five "natural" athletes were asked to participate in a study of motor skills. As part of the study they

learned to balance on a freestanding ladder (a skill that requires you to make quick, precise

adjustments) and to perform the two-hand coordination task (an eye-hand coordination task). The

scores are shown below.

Calculate a correlation coefficient and write a conclusion about motor skills in excellent athletes. Construct a scatterplot.

Initials Ladder Coordination

TH 8 1.7

IS 11 1.0

IS 3 1.2

TR 7 1.5

UE 9 0.6