Dental statistics - Essay Example

In other words, the given mean is calculated from the whole population and the other one is from a sample. Yes, increase in sample size will affect the mean value and it will produce a different result from the result which is calculated from sample size of 30 20-year-old dental students. In fact more accurate results can be obtained by increasing the sample size because more cases are under consideration by increasing sample size. Changes in sample size produce different result because frequencies corresponding to different values of variable (missing teeth) change by changing the sample size.

For example if we consider a sample of 35 20-year-old dental students and their frequency distribution is given as; So, it is clear from the above example, if we change the sample size the value of mean also changes. The mean value of sample of 35 is more accurate than the mean value of sample size of 30. Similarly, the standard deviation of later is also less which means that the value of variable in the data of large size is cluster near the sample mean. A survey was conducted to determine the number of decayed, missing and filled teeth of 20 year old dental students in a particularly country.

It was not possible to check out all the 20 year old dental students of a country therefore, a group of 30 students of age 20 years was taken from the population and observed. It was observed that the student took number of missing teeth from 0 to 12. The mean value calculated from the observed values is 5.967; it means that most of the students in the sample have 6 decayed, missing and filled teeth. With the help of mean and frequencies standard deviation has also been calculated which gives an idea of dispersion of number of missing teeth from 6.

The standard deviation is 3.05 which reflect that there is less dispersion in the data. In other words, that number of missing teeth of students in the sample size of 30 has