STAT213
Worksheet #1
1)
Monthly
revenues for a sample of 30 companies are as follows in units of $10,000:
|
4.5 |
4.8 |
5.3 |
5.9 |
4.6 |
4.8 |
4.9 |
5.2 |
4.1 |
5.8 |
|
4.6 |
4.9 |
5.1 |
5.3 |
3.8 |
3.9 |
2.8 |
6.4 |
4.7 |
7.1 |
|
7.8 |
7.3 |
2.9 |
3.2 |
4.9 |
5.2 |
4.5 |
6.2 |
5.7 |
4.3 |
Form a stem and leaf plot with a
leaf unit of 0.1
2)
Using
a class width of 1, create a frequency table.
3)
What
percentage of the companies have monthly revenues
below $40,000 (16.67%)
4)
What
percentage of the companies have monthly revenues of
$50,000 or more? (43.33%)
5)
Using
the same class width of 1, construct a bar chart of the data using a frequency
scale. Does the data appear bell-curved? (the data appears bell-curved)
6)
Compute
the mean, standard deviation and median of the data, rounding to the nearest
dollar. (mean = 50,167; standard deviation = 11,832; median = 49,000)
7)
Compute
Pearson’s coefficient of skewness. If we use the
criterion that the data is symmetric if the magnitude of the skewness is less than 0.5, is the data symmetric? (cs = 0.2958; the data is symmetric)
8)
Construct
a box plot of the data. Does the data contain any outliers? (q1=4.5; q3=5.7;
7.8 is a mild outlier)
A focus
group with 15 respondents asked how many TV shows per week they watched. These
were the results:
|
7 |
11 |
11 |
6 |
10 |
|
9 |
15 |
11 |
10 |
10 |
|
15 |
10 |
14 |
11 |
32 |
9)
Form
a stem and leaf plot with a stem unit of 10. (see key)
10)
Using
a class width of 4, create a frequency table. Use 6-9 as the first class. (see
key)
11)
Using
the same class width of 4, construct a polygon of the data using a relative
frequency scale. (see key)
12)
Compute
Pearson’s coefficient of skewness. What is the degree
of skewness? (cs = 0.5624;
slightly skewed right)
13)
Does
the data contain any outliers? (32 is an extreme outlier)
14)
What
is the mode? (10 and 11)
15)
What
is the range? (26)
16)
If
the outlier is removed, show why the mean is affected more than the median.
(see key)
17)
Based
on the results of a survey, a frequency table was made of the amount that
household spend per week on groceries:
|
Class |
Frequency |
Percent |
Cum. % |
|
50
to less than 100 |
46 |
9.20% |
9.20% |
|
100
to less than 150 |
151 |
30.20% |
39.40% |
|
150
to less than 200 |
202 |
40.40% |
79.80% |
|
200
to less than 250 |
91 |
18.20% |
98.00% |
|
250
to less than 300 |
10 |
2.00% |
100.00% |
Compute the group mean and group standard
deviation. Round to the nearest cent. (mean = 161.80; standard
deviation = 46.48)
From the textbook:
Section 2-2 Q5-12 (page 39) Round
the accuracy to 3 decimals to match the solutions in the back of the textbook.
Section 2-4 Q1-4 (pages 66-67) Note: midrange =
(highest value + lowest value)/2
Section 2-5 Q1-4 (pages 83-84)
Section 2-6 Q17-24 (page 96) Note that Table
2.9 is on page 91.
Section 2-7 Q12 (page 105)