Anthropology: Skull dimensions

Stat 101: Extra Credit #7[3]DUE:Nov. 28Name: ______

Print this page out AFTER you have inserted the statistics table and histograms.

DATA DESCRIPTION: The following data represent the maximum breadths (widths in mm) of a collection of male Egyptian skulls from 4000 BC. Use SPSS to address the following items.

SPSS NOTES: When you open SPSS select the Cancel button in the dialog box. That will leave you with a blank Data Editor. Enter the data listed below into the first column. As you enter data into the columns a variable name such as VAR00001 will be made automatically by SPSS. You may find it easier to rename these columns to the names noted in items 1 - 4. To do so, click on the “Variables” tab at the bottom of the Data Editor (lower left) and type the new names in the column containing the VAR0001, etc. names.

DATA: 131 119 138 125 129 126 131 132 126 128 128 131

1) Skull: Enter the data above into the first column.

2) Skull_plus20: In a new SPSS column add 20 to each of the original values (e.g. 131 becomes 151).

3) Skull_times10: In a third column multiply each of the original values by 10 (e.g. 131 becomes 1310).

4) Skull_outlier: In a fourth column copy the data from the Skull variable, but change only the first value from "131" to "1311."

STATISTICS ACQUISTION:

5) Obtain the following descriptive statistics for all four variables: Mean, Median, Mode, SD, Minimum, Maximum, Q1, Q3. [Note: move all variables to the right so that all statistics appear in one table.]

6) Place the statistics table (not the frequency tables) into your response where noted below.

7) Obtain histograms of the variables Skull and Skull_outlier. Place the two histograms where noted (see #11).

DATA ANALYSIS:

INSERT STATISTICS TABLE HERE

8) [1[ Considering the Skull and Skull_plus20 variables:

  • How is the mean affected if the same constant (here, 20) is added to each value in the data set?
  • How is the median affected if the same constant is added to all values in the data set?
  • How is the standard deviation affected if the same constant is added to each value in the data set?

9) [1] Considering the Skull and Skull_times10 variables:

  • How is the mean affected if each original score is multiplied by a constant (here, 10)?
  • How is the median affected if each original score is multiplied by a constant (here, 10)?
  • How is the standard deviation affected if each original scores is multiplied by a constant (here, 10)?

10) [.5] Considering the Skull and Skull_outlier variables:

  • How is the mean affected by inclusion of this extreme score (here, 1311)?
  • How is the median affected by inclusion of this extreme score?
  • How is the standard deviation affected by inclusion of this extreme score?

11) [.5] Considering the Skull and Skull_outlier histograms

INSERT HISTOGRAMS HERE.

  • Distribution shapes: Compare the histograms of the variables Skull and Skull_outlier. For Skull_outlier, did inclusion of an outlier affect the shape of the distribution? If so, how would you characterize the Skewness of the distribution?