Descriptive Statistics - Find % of measurement in a certain range

In summary, the conversation discusses a problem statement regarding a set of measurements with a normal distribution. The measurements have a mean of 50 and a standard deviation of 1. The question asks what percentage of measurements would be expected in the range 48 < x < 50. The solution suggests using the Empirical Rule to determine the expected percentages, rather than a probability calculation. A link is provided for further explanation and assistance.
  • #1
oceanwalk
6
0
1. The problem statement:
A set of measurements of a parameter x has a normal distribution with mean of 50 and standard deviation of 1. If there are a very large number of measurements, approximately what percentage of measurements would you expect to be in the range 48 < x < 50?


Relevant equations
I have no idea


3. The Attempt at a Solution
Again, I have no idea.
 
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  • #2
Normal distribution refers to the bell curve. Here's a link to check out. Go through the explanation and try to work it out. After you've given it a shot and you end up getting stuck, let us know and we'll help you out.

http://en.wikipedia.org/wiki/Normal_distribution
 
  • #3
if the measurements are normally distributed, in a large sample of them you should see the percentages follow those given in the Empirical Rule. That rule tells you the percentages to expect from [tex] \mu - k \sigma [/tex] to [tex] \mu + k \sigma [/tex] for the cases k = 1, 2, and 3. Use that, with a handily drawn sketch, to answer your question (I don't get that the intent is to use a probability calculation here).
 

1. What is descriptive statistics?

Descriptive statistics is a branch of statistics that involves summarizing and organizing data in order to describe or understand a particular phenomenon or population.

2. What is the purpose of using descriptive statistics?

The purpose of using descriptive statistics is to provide a clear and concise summary of a data set, which can help in identifying patterns, trends, and relationships within the data.

3. How do you find the percentage of measurements in a certain range?

To find the percentage of measurements in a certain range, you first need to determine the total number of measurements in the data set. Then, you can calculate the number of measurements that fall within the desired range and divide it by the total number of measurements. Finally, multiply the result by 100 to get the percentage.

4. What are some common measures of central tendency used in descriptive statistics?

Some common measures of central tendency include mean, median, and mode. Mean is the average of all the values in a data set, median is the middle value when the data is arranged in ascending or descending order, and mode is the most frequently occurring value in a data set.

5. How is descriptive statistics used in research?

Descriptive statistics is used in research to summarize and describe the characteristics of a sample or population. It helps researchers to understand the data and make informed decisions based on the results. It is also used to compare different groups or variables and identify any significant differences or relationships between them.

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