① Find the difference between the maximum value and the minimum value;
(2) Determine the distance between groups and the number of groups. In order to avoid that a data is both the starting point and the end point, resulting in repeated calculation, the grouping interval is "left closed and right opened";
(3) Determine the demarcation point;
④ Column frequency distribution table.
Solution: (1) The process of making frequency distribution table and frequency histogram of samples is as follows:
① Find the extreme value range. In the above data, the extreme value range is 364.4438+0-362.438+0 =1.9.
② Determine the distance and the number of groups.
If the distance between groups is set to 0.25, the number of groups is 8 in 1.9÷0.25=7.6.
③ Determine the demarcation point.
According to the characteristics of data, the starting point of 1 group can be 362.50, and the ending point of 1 group can be 362.75, and the obtained groups are [362.50, 362.75, 363.00], …, [364.25, 364.50] respectively.
④ Column frequency distribution table.
Table below.
group
Number of packages
frequency
[362.50,362.75)
five
0.062 5
[362.75,363.00)
six
0.075
[363.00,363.25)
eight
0. 1
[363.25,363.50)
23
0.287 5
[363.50,363.75)
16
0.2
[363.75,364.00)
13
0. 162 5
[364.00,364.25)
seven
0.087 5
[364.25,364.50)
2
0.025
total
80
1.000 0
⑤ Draw the histogram of frequency distribution.
Frequency distribution histogram (as shown below)
(2) Connect the midpoint of each small rectangle in the frequency histogram to obtain a frequency distribution line chart, as shown in the following figure.
As can be seen from the above table, most parts fall within [363.25, 363.50] and most parts fall within [362.75, 364.25].