Stats Practice

Measures of Central TendencyOn a quiz given to 5 students, the

scores were as follows:  17, 19, 20, 22, 22What is the mean?

20What is the median?

20What is the mode?

22

Skewed DistributionsOut of 108 students in Mrs.

O'Connor's AP Psychology classes, 107 people earned an A on the Chapter 2 Exam.  One person earned an F.  What happened to the mean as a result of the one F?  Went down

What type of distribution is this?Negative

Standard DeviationTwo tests were given.  The standard

deviation of the first test was 10.  The standard deviation of the second test was 15.  Which test had scores that were more spread out?Second test

Z-scoresRyan earned a 70 on a normally

distributed test with a mean of 60.  The standard deviation was 5.  What is Ryan's z-score?+2

Alyssa earned a 65 on a normally distributed test with a mean of 80.  The standard deviation was 15.  What is Alyssa's z-score? -1

Percentile RankFor a language test with normally distributed

scores, the mean was 75 and the standard deviation was 15. Approximately what percentage of test-takers scored a 60 or above?84%

For a language test with normally distributed scores, the mean was 40 and the standard deviation was 10. Approximately what percentage of test-takers scored a 50 or above?16%

Percentile Rank Dr. Zimbardo conducted an intelligence test in which

the scores were normally distributed. The mean was 85 and the standard deviation was 10. What percentage of people scored a 95 or above? Show your work/ distribution.

16% In the above question, what was the variance? 100

Dr. Milgram conducted a strength test in which the scores were evenly distributed. The mean was 115 and the standard deviation was 5. What percentage of people scored 105 or above? Show your work/distribution.

97.5% In the above question, what was the variance? 25