What methods did we employ in this experiment?

On each trial you rated the humor of a joke by moving a slider. There were no right or wrong answers to this rating, as we are measuring your personal sense of humor for various jokes.

There is no specific prediction because different people find different jokes funny. What the experiment provides is a way of measuring one aspect of your personal sense of humor. Namely, how funny did you find these jokes, compared to other people? The trial-by-trial data assign numbers to your ratings of the jokes. A bigger number means you found the joke to be more funny. The maximum is 10 and the minimum is 0 (not funny at all).

The numbers by themselves do not mean very much, but they allow you to compare your sense of humor to other people's. This frequency table is from a database where 3187 people provided ratings for the very same set of jokes. You will use this table to compute the percentile rank corresponding to your humor measure score.

Exact limits Midpoint f cf

9.5 to 10.5 10 82 3187

8.5 to 9.5 9 194 3105

7.5 to 8.5 8 478 2911

6.5 to 7.5 7 813 2433

5.5 to 6.5 6 947 1620

4.5 to 5.5 5 411 673

3.5 to 4.5 4 145 262

2.5 to 3.5 3 67 117

1.5 to 2.5 2 31 50

0.5 to 1.5 1 16 19

-0.5 to .05 0 3 3

You will compute the percentile rank. This is the percentage of humor measurements in the database that are smaller than or equal to your humor measurement. Thus, if your percentile rank is 10%, this indicates that only 10% of the participants in the database had a smaller sense of humor than you. This would suggest that, relative to other people, you do not find these jokes to be particularly funny.

Formulas

Different formulas are used to calculate a percentile rank depending on what kind of information you have available. To compute the percentile rank for a score, X, from a frequency table, use:

PRX={cf+(fi)(Xll)/wn}(100)

The terms in the equation are:

X = the score for which the percentile rank is to be determined

cf = the cumulative frequency of scores below the interval containing the score X

ll = the exact lower limit of the interval containing X

w = the width of class interval containing X

fi = the frequency of scores in the interval containing X

n = the total number of scores in the database

Answer the questions using the data below.

Sum of joke ratings:

(Your answer must exactly equal the correct value.)

Mean of joke ratings (X). This is the score for which the percentile rank is to be determined:

(The difference between your answer and the correct value must be less than 0.001.)

cf, the cumulative frequency of scores below the interval containing the score X:

(Your answer must exactly equal the correct value.)

ll, the exact lower limit of the interval containing X:

(Your answer must exactly equal the correct value.)

w, the width of class interval containing X:

(Your answer must exactly equal the correct value.)

fI, the frequency of scores in the interval containing X:

(Your answer must exactly equal the correct value.)

n, the total number of scores in the database:

(Your answer must exactly equal the correct value.)

The percentile rank of your humor measure, PRX:

(The difference between your answer and the correct value must be less than 0.01.)

Trial Rating of joke

1 6.0

2 4.0

3 4.0

4 7.0

5 4.0

6 4.0

7 6.0

8 6.0

9 6.0

10 4.0

11 7.0

12 4.0

13 7.0

14 7.0

15 3.0

16 3.0

17 4.0