The meaningful tabulation of data is the one of the first steps that are performed in any statistical study. The data is collected by sampling and summarized in a table, which is called frequency distribution, in which each variable value associated with it certain numbers representing the number of times it has appeared, their ratio with respect to other variable values, etc. Therefore, a frequency distribution of data is divided into classes grouping together with their frequencies and relative percentage (Ott, 2003, 87). Frequency distributions vary depending on whether they correspond to a discrete variable or a continuous variable.
Hours of Light Bulb (Binned)
Frequency
Percent
Valid Percent
Cumulative Percent
Valid
<=680
1
2.1
2.1
2.1
681-740
2
4.2
4.2
6.2
741-800
1
2.1
2.1
8.3
801-860
10
20.8
20.8
29.2
861-920
13
27.1
27.1
56.2
921-980
12
25.0
25.0
81.2
981-1040
5
10.4
10.4
91.7
1041-1100
4
8.3
8.3
100.0
Total
48
100.0
100.0
The table above shows the frequency distribution for the given data set. As my registration ID is 0706526, therefore the value of X becomes 0, which is replaced by 5 in the data set to obtained proper executable data. Further, the number has been grouped into the classes; there were 48 observations in total. The result of 100-watt light bulbs is divided into 7 intervals of width of 60. In this case, the intervals are the length of life (in hours) of a sample of forty eight 100-watt light bulbs produced by a manufacturer.
Descriptive statistics holds great importance in different walk of human life. Descriptive statistics is the tabulation of data presentation in graphical. The statistical techniques are applied widely in marketing, accounting, consumer surveys, sports, education, politics and medicines due to the need of decision-making. The purpose of the data in the form of descriptive statistics draw conclusions and make policy (for analysis) solutions, based on available data (Mann, 1995, 23).
Frequency Distribution Histogram
The histogram is a widely used tool, especially for summarizing data discrete or continuous measured in an interval scale. It is often used to show the main features of the data distribution in a practical way. A histogram divides the possible values ??of the data into classes or groups. For each group, a rectangle is constructed whose base corresponds to the values ??of this group, and the size of the rectangle is proportional to the number of observations in the group. This means that the rectangles are of different heights. A histogram has an appearance similar to a vertical bar graph, but when the variables are continuous, there is no gap between the bars.
The above histogram for the frequency distribution shows that maximum numbers of the frequencies i.e. 13 were observed in the fifth interval i.e. 861-920, the second highest frequencies i.e. 12 were observed in the 4th interval i.e. 921-980. However, the lowest frequencies were found in the 1st and 3rd interval, which is 1.
Question 2
Sales of 2010 model light trucks and sport utility vehicles for the Ford Motor Company far outpaced their 2009 counterparts according to a Wall Street Journal article. The following table indicates unit sales for selected vehicles for March 2009 and March 2010.