How do i read a frequency graph?

In summary, the conversation discusses how to find the average and standard deviation using a frequency graph. The individual asking the question provides some values and expressions, but they do not seem to be correct. The expert summarizes that to find the average, one would multiply the frequency by the midpoint of each category and then divide by the total frequencies. To find the standard deviation, one would use the formula root(x-mean)^2/n.
  • #1
Sirsh
267
10
How do i read a frequency graph??

If i have. a time required of 5-9 and a a frequency of 5. how do i find the average? do i do 9-4*6 or 9*5+5*9/5 ?? thanks.
 
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  • #2


Sirsh said:
If i have. a time required of 5-9 and a a frequency of 5. how do i find the average? do i do 9-4*6 or 9*5+5*9/5 ?? thanks.

I don't think you have given a clear explanation of what you are given, but I'll do my best to explain what I think you are asking. Also, I don't think that either of the values you gave is correct. 9 - 4*6 = 9 - 24 = -15, which doesn't make any sense. If you meant (9 - 4)*6, that's 5*6 = 30, and I don't see that this number has anything to do with anything. For the other expression, 9*5+5*9/5 = 45 + 9 = 54, but that doesn't have anything to do with anything, either.

I believe that the time required, 5 - 9, means a time interval of 5 to 9 time units of some kind, and the frequency of 5 means that 5 times were between 5 and 9 (sec? min? hours?).

The average time would be (5 + 9)/2 = 7
 
  • #3


Sorry i meant.
|Time required to complete test| Frequency | Midpoint |
| 5-9 | 6 | 7 |
| 10−14 | 12 | 12 |
| 15−19 | 25 | 17 |
| 20−24 | 34 | 22 |
| 25−29 | 16 | 27 |
| 30−34 | 7 | 32 |

What would be the mean of this? sorry.

Would i just do total of (frequency * midpoint)/amount scores?
 
  • #4


Something like that. For each category, multiply the frequency by the midpoint of the category. Add all these products and divide by the total frequencies. IOW,
(f1 * m1 + f2 * m2 + ... + fn * mn)/(f1 + f2 + ... + fn)
 
  • #5


Thank you. Do you know how i'd go around getting the stadard deviation? Is it root(x-mean)^2/n?
 

1. What is a frequency graph?

A frequency graph, also known as a frequency distribution graph, is a visual representation of the frequency of data values in a dataset. It shows the number of times each value occurs in the data, and is often used to analyze and understand patterns and trends in the data.

2. How do I interpret a frequency graph?

To interpret a frequency graph, start by looking at the x-axis, which represents the data values. Then, look at the y-axis, which represents the frequency of each value. The height of each bar or column on the graph represents the frequency of that particular value. You can also look for patterns, such as a bell-shaped curve, to understand the distribution of the data.

3. What are the different types of frequency graphs?

There are several types of frequency graphs, including histograms, bar graphs, and line graphs. Histograms are used for continuous data, while bar graphs are used for categorical data. Line graphs are used when there is a time component to the data. Each type of frequency graph has its own unique characteristics and is used for different types of data.

4. How do I create a frequency graph?

To create a frequency graph, you will first need to collect and organize your data. Then, determine the type of frequency graph that is most appropriate for your data. Use a spreadsheet or graphing software to plot the data on the graph, making sure to label the axes and add a title. Once the graph is created, you can analyze and interpret the data.

5. What are some common mistakes when reading a frequency graph?

One common mistake when reading a frequency graph is misinterpreting the data values on the x-axis. Make sure to pay attention to the scale and intervals on the axis. Another mistake is not considering the units of the data. Make sure the units are consistent and clear on the graph. Additionally, be careful not to misinterpret the height of a bar or column, as it represents the frequency and not the actual value of the data.

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