Question

The accompanying frequency distribution represents the square footage of a random sample of 500 houses that are owner occupied year round. Approximate the mean and standard deviation square footage.

The mean square footage is x bar = ?

Table

Square footage		Frequency
0 ? 499?1		9
500 ? 999?1		13
?1,000 - ?1,499		33
?1,500 - 1,999		115
?2,000 - 2,499		125
?2,500 - 2,999		83
?3,000 - 3,499		45
?3,500 - ?3,999		41
?4,000 ? ?4,499		26
?4,500 ? ?4,999		10

Answer 1

x               f              fx             x -                    (x - )²                          f (x -)²

250          9           2250          - 2194                   4813636                         43322724

750         13          9750           - 1694                  2869636                        37305268

1250       33          41250          - 1194                 1425636                         47045988

1750       115       201250            - 694                 481636                           55388140

2250        125     281250            - 194                  37636                            4704500

2750        83        228250             306                  93636                           7771788

3250        45       146250              806                 649636                         29233620

3750        41      153750             1306                1705636                         69931076

4250         26     110500              1806              3261636                          84802536

4750         10      47500               2306             5317636                          53176360

-----------------------------------------------------------------------------------------------------------------------------

Total          500   1222000             -                      -                                     432682000

(a)
mean =

standard deviation =