ACTIVITY
/ EXERCISES
1.
The number of incorrect answers on a
true-false competency test for a random sample of 15 students were recorded as
follows: 2, 1, 3, 0, 1, 3, 6, 0, 3, 3, 5, 2, 1, 4, and 2. Find
(a)
the mean;
(b)
the median;
(c)
the mode.
2.
The number of building permits issued last
month to 12 construction firms in a small Midwestern city were 4, 7, 0, 7, 11,
4, 1, 15, 3, 5, 8, and 7. Treating the data as a population, find
(a)
the mean;
(b)
the median;
(c)
the mode.
3.
The
reaction times for a random sample of 9 subjects to a stimulant were recorded
as 2.5, 3.6, 3.1, 4.3, 2.9, 2.3, 2.6, 4.1, and 3.4 seconds. Calculate
(a)
the mean;
(b)
the median.
4.
The employees of a local manufacturing
plant pledged the following donations, in dollars, to the United Fund: 10, 40,
25, 5, 20, 10, 25, 50, 30, 10, 5, 15, 25, 50, 10, 30, 5, 25, 45, and 15.
Treating the data as a population, calculate
(a)
the mean;
(b)
the mode.
5.
According to ecology writer Jacqueline
Killeen, phosphates contained in house-hold detergents pas right through our
sewer system causing lakes to turn into swamps that eventually dry up into deserts.
The following data show the amount of phosphates per load of laundry, in grams,
for a random sample of various types of detergents used according to the
prescribed directions:
|
Laundry Detergents
|
Phosphates
per load (gm)
|
|
A & P Blue Sail
|
48
|
|
Dash
|
47
|
|
Concentrated All
|
42
|
|
Cold Water All
|
42
|
|
Breeze
|
41
|
|
Oxydol
|
34
|
|
Ajax
|
31
|
|
Sears
|
30
|
|
Cold Power
|
29
|
|
Bold
|
29
|
|
Rinso
|
26
|
For
the given phosphate data, find
(a)
the mean;
(b)
the median;
(c)
the mode.
