BACK TO DESCRIPTIVE STATISTICS:  LET’S TEST OUR PHYSICS EXAMPLE USING STATISTICS.

1. STICK A SMALL PIECE OF TAPE TO A HARD SURFACE TO ACT AS A TARGET.
2. DROP A NICKLE (QUARTER IS TOO HEAVY, PENNY/DIME TOO LIGHT) ONTO THE TAPE FROM A HEIGHT OF ABOUT TWO (2) FEET. WHEN IT STOPS ROLLING OR BOUNCING, MEASURE THE DISTANCE FROM THE COIN’S CENTER TO THE CENTER OF THE TAPE. MEASURE TO THE NEAREST HALF INCH (E.G. 3.5 NOT 3.437619)
3. REPEAT THIS THIRTY (30) TIMES (30 IS A “MAGIC” NUMBER IN STATISTICAL SAMPLING AS YOU WILL SEE LATER IN THE COURSE).
4. THEN, DROP THE SAME NICKLE FROM A HEIGHT OF AROUND FOUR (4) FEET OR TWICE THE FIRST HEIGHT THIRTY (30) TIMES AND MEASURE THOSE DISTANCES.
5. TYPE THESE DISTANCES IN TWO ROWS (not columns) WITH NO COMMAS SO I CAN COPY AND PASTE THEM INTO EXCEL FOR NEXT WEEK’S TOPIC.
6. NOW, LOOK AT THOSE TWO SETS OF NUMBERS (THE RAW DATA) AND DESCRIBE WHAT YOU SEE BY JUST LOOKING AT THE TWO SETS OF NUMBERS. ANYTHING? WHAT ARE WE TRYING TO SHOW OR WHAT DO YOU EXPECT THESE DATA TO SHOW ? DO JUST THE ROWS OF NUMBERS TELL YOU ANYTHING?
7. CONTINUING WITH “DESCRIPTIVE STATISTICAL ANALYSIS” PLOT YOUR TWO SETS OF DISTANCE DATA ON THE GRAPH PAPER FROM THIS LINK (PRINT OUT ON 8.5 X 11 OFFICE PAPER &(PLEASE USE IT SO EVERYONE HAS THE SAME FORMAT).  GRAPH PAPER FOR WK2-D2-TOPIC
8. WE WILL CALCULATE ONE STATISTIC THIS EARLY IN THE COURSE: THE MEAN (AVERAGE). ADD UP EACH SET OF DISTANCES AND DIVIDE EACH OF THOSE SETS BY 30 (THE NUMBER OF DATA POINTS IN EACH SET) TO GET THE MEAN. MATHEMATICALLY THIS WOULD BE SHOWN AS: m = Σx/n WHERE “x” IS EACH DATA POINT AND “n” IS THE TOTAL NUMBER OF DATA POINTS INVOLVED. (MATH IS REALLY LIKE ANOTHER LANGUAGE WITH ITS OWN SYMBOLS AND CONTEXT)
9. NOW, ON YOUR TWO DATA PLOTS DRAW A HORIZONTAL LINE WHERE YOUR CALCULATED MEAN IS. SEE HOW SOME DATA POINTS ARE ABOVE THIS LINE AND SOME BELOW? MEASURE THESE 30 DISTANCES WITH THE DISTANCES ABOVE THE LINE AS POSITIVE NUMBERS AND THOSE BELOW THE LINE AS NEGATIVE NUMBERS. ADD THEM ALL UP AND WHAT VALUE DO YOU GET? (RATHER THAN MEASURING SIMPLY SUBTRACT YOU CALCULATED MEAN FROM EACH DATA MEASUREMENT).
10.  BOTTOM LINE: LOOK AGAIN AT EACH PLOT AND HOW THE TWO SETS OF DATA PLOTS ARE SCATTERED AROUND THE MEAN. DO THE PLOTS, THE CALCULATED MEAN OR THE TWO ROWS OF NUMBERS TELL YOU ANYTHING ABOUT THE DIFFERENCES THE DROP HEIGHT MAKES AND WHETHER IT CONFORMS TO THE F = MA FORMULA? EXPLAIN THIS IN YOUR POST.
11. FOR REVIEWS (2 REQUIRED), NOTE HOW YOUR OBSERVATIONS AGREE/DISAGREE WITH YOUR CLASSMATES – BUT LOOK FOR CLASSMATE POSTS THAT DIFFER AT LEAST SOMEWHAT FROM YOURS SO THAT YOU EITHER GET A NEW PERSPECTIVE, OR CAN HELP THEM WITH THEIR INTERPRETATION.