What value do you get for ΣX – 1 for the following data set? 1, 3, 5, 6

a) What is the main purpose of a z-score (i.e., what does it tell us?)? b) Imagine that your friend tells you her z-score on an extroversion scale is  0.0. What does this mean? Your interpretation of this score does not need to be long, but it should fully explain the score.

The Bigfoot Field Researchers Organization (www.bfro.net) maintains a database of bigfoot/Sasquatch sightings and related reports. According to the BFRO database as of January 2011 the mean number of reports per county in the state of Washington is 12.59 (standard deviation = 14.19). Here are the z-scores for three specific counties: Whitman County: z = -0.89    Cowlitz County: z = -0.03      Skamania County: z = +2.78   Which of these three counties is most representative of the typical county in Washington in terms of the number of Bigfoot reports?

A researcher conducts an experiment to determine whether moderate doses of St. John’s wort have any effect on the memory of college students.  For this study, what is the independent variable?

For the following frequency distribution, what is the value of ΣX? X f 5 2 4 4 3 1 2 3

You have a score of X = 20 on a quiz. Which set of statistics would give you the best grade on the quiz?

Is there a problem with this graph? Explain.                                                            Fiscal Quarter

Fill in the missing values. X f p % cf  c% 20 3 0.06 5.66 53 100.00 19 0.06 5.66 50 18 6 0.11 11.32 47 88.68 17 8 0.15 15.09 41 77.36 16 5 0.09 9.43 62.26 15 5 9.43 28 52.83 14 7 0.13 13.21 23 43.40 13 0.09 9.43 16 12 6 0.11 11.32 11 20.75 11 2 3.77 9.43 10 0.06 5.66 3 5.66 Total 53

Fill in the missing values. X f p % cf  c% 20 2 0.04 3.77 53 100.00 19 0.08 7.55 51 18 6 0.11 11.32 47 88.68 17 8 0.15 15.09 41 77.36 16 6 0.11 11.32 62.26 15 5 9.43 27 50.94 14 4 0.08 7.55 22 41.51 13 0.13 13.21 18 12 6 0.11 11.32 11 20.75 11 2 3.77 9.43 10 0.06 5.66 3 5.66 Total 53

Imagine that we have a normal distribution of Exam scores for Psychology 210 with a mean of 75 and a standard deviation of 5. If I randomly drew a score of 90, would this be surprising? Explain your answer.