### 4 April (Task 1) Chap 16 Data Handling: Histograms - What is it? [5 min]

Carry out a search in the internet to find out how histogram is used in real world.
Briefly summarise how it is used.
Include the URL of the website where you found the imformation.

1. Histograms are used to plot density of data, and often for density estimation: estimating the probability density function of the underlying variable.

Source:http://en.wikipedia.org/wiki/Histogram

2. A histogram is a graphical representation, showing a visual impression of the distribution of data.

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5. In statistics, a histogram is a graphical representation, showing a visual impression of the distribution of data. http://en.wikipedia.org/wiki/Histograms
Matthew Goh

6. Histograms are best used when there is large amount of data presented in a table. Histograms are like a snapshot as opposed reflecting a process' performance over time like run charts and control charts do. A histogram makes it easy to see where the majority of values fall in a measurement scale, and how much variation there is. You will want to construct a histogram when you want to do the following:

Summarize large data sets graphically. A data set presented in a table isn’t easy to use. You can make it much easier to understand by summarizing it on a tally sheet and organizing it into a Histogram.
Compare process results with specification limits. If you add the process specification limits to your Histogram, you can determine quickly whether the current process was able to produce "good" products. Specification limits may take the form of length, weight, density, quantity of materials to be delivered, or whatever is important for the product of a given process.
Communicate information graphically. The team members can easily see the values, which occur most frequently. When you use a Histogram to summarize large data sets, or to compare measurements to specification limits, you are employing a powerful tool for communicating information.
Use a tool to assist in decision-making. Certain shapes, sizes, and the spread of data have meanings that can help you in investigating problems and making decisions. Bear in mind that if the data you have in hand aren’t recent, or you don’t know how the data were collected, it’s a waste of time trying to chart them. Measurements cannot be used for making decisions or predictions when they were produced by a process that is different from the current one, or were collected under unknown conditions.

Source: http://www.brighthub.com/office/project-management/articles/13445.aspx

7. The census found that there were 124 million people who work outside of their homes. An interesting feature of this graph is that the number recorded for "at least 15 but less than 20 minutes" is higher than for the bands on either side. This is likely to have arisen from people rounding their reported journey time. http://en.wikipedia.org/wiki/Histogram#Examples

8. Histograms are used to plot trend

9. Histogram is used to plot data by drawing rectangles directly next to each other to compare the data.

http://quarknet.fnal.gov/toolkits/new/histograms.html

Ben Ng (18) S1-02

10. A histogram is a graphical representation, showing a visual impression of the distribution of data. Histograms are used to graphically summarize and display the distribution and variation of a process data set.

URL: wikipedia.org/

11. Histograms are used to plot density of data, and often for density estimation: estimating the probability density function of the underlying variable.
http://en.wikipedia.org/wiki/Histogram

12. histogram is a summary graph showing distribution of data points measured that falls within various class-intervals. A class interval is a division of a range of values into sets of non-overlapping intervals for plotting a histogram. It is drawn with rectangles side by side with the area of each rectangle being proportional to the frequency of the observations falling into the corresponding class-interval.

http://cnx.org/content/m13423/latest/

13. histogram is a graphical representation, showing a visual impression of the distribution of data. It is an estimate of the probability distribution of a continuous variable

RYAN YEO
Sources:http://www.netmba.com/statistics/histogram/ and http://en.wikipedia.org/wiki/Histogram

14. A histogram is a representation of a frequency distribution by means of rectangles whose widths represent class intervals and whose areas are proportional to the corresponding frequencies.

http://quarknet.fnal.gov/toolkits/new/histograms.html

15. A Histogram is a vertical bar chart that shows the distribution of a set of data. It is used compare large data and summarize data. http://www.saferpak.com/histogram_articles/howto_histogram.pdf

16. Histograms are used:
to display large amounts of data values in a simple chart,
to tell relative frequency of occurrence,
to easily see the distribution of the data
to see if there is variation in the data
to make future predictions based on the data

http://www.brighthub.com/office/project-management/articles/13307.aspx

17. Histograms are used to plot density of data, and often for density estimation: estimating the probability density function of the underlying variable.
http://en.wikipedia.org/wiki/Histogram

18. a histogram is a graphical representation, showing a visual impression of the distribution of data. It is an estimate of the probability distribution of a continuous variable. A histogram consists of tabular frequencies, shown as adjacent rectangles, erected over discrete intervals (bins), with an area equal to the frequency of the observations in the interval. The height of a rectangle is also equal to the frequency density of the interval

Sauce:http://en.wikipedia.org/wiki/Histogram

19. The histogram is a summary graph showing a count of the data points falling in various ranges. The effect is a rough approximation of the frequency distribution of the data. The groups of data are called classes and in the context of a histogram , they are known as bins. They are just like containers that can accumulate data and "fill up" at a rate same as the frequency of the data class.

20. In statistics, a histogram is a graphical representation, showing a visual impression of the distribution of data. It is an estimate of the probability distribution of a continuous variable and was first introduced by Karl Pearson. A histogram consists of tabular frequencies, shown as adjacent rectangles, erected over discrete intervals (bins), with an area equal to the frequency of the observations in the interval. The height of a rectangle is also equal to the frequency density of the interval, i.e., the frequency divided by the width of the interval. The total area of the histogram is equal to the number of data. A histogram may also be normalized displaying relative frequencies. It then shows the proportion of cases that fall into each of several categories, with the total area equaling 1. The categories are usually specified as consecutive, non-overlapping intervals of a variable. The categories (intervals) must be adjacent, and often are chosen to be of the same size.
Histograms are used to plot density of data, and often for density estimation: estimating the probability density function of the underlying variable. The total area of a histogram used for probability density is always normalized to 1. If the length of the intervals on the x-axis are all 1, then a histogram is identical to a relative frequency plot.
An alternative to the histogram is kernel density estimation, which uses a kernel to smooth samples. This will construct a smooth probability density function, which will in general more accurately reflect the underlying variable.
The histogram is one of the seven basic tools of quality control.

Source: http://en.wikipedia.org/wiki/Histogram

21. A histogram is one of the basic quality tools. It is used to graphically summarize and
display the distribution and variation of a process data set. A frequency distribution
shows how often each different value in a set of data occurs. The main purpose of a
histogram is to clarify the presentation of data. You can present the same information in
a table; however, the graphic presentation format usually makes it easier to see
relationships. It is a useful tool for breaking out process data into regions or bins for
determining frequencies of certain events or categories of data. These charts can help
show the most frequent.