frequency distribution table assumed mean

The number which tells us how many times a particular data appears is called the frequency. For example, 2 marks have been scored by five students which means marks 2 occurs five times. Therefore, the frequency of score 2 is five. Similarly, the frequency..

A teacher gave a test to a class of 26 students. The maximum mark is 5. The marks obtained by the pupils are: Such data as above is called ungrouped (or raw) data. We may arrange the marks in ascending or descending order. The data so represented is called an array. The difference between the great..

Cumulative frequency is obtained by adding the frequency of a class interval and the frequencies of the preceding intervals upto that class interval. This is explained by an example below. The following frequency distribution table gives t..

Frequency Polygon - In a frequency distribution, the mid-value of each class is obtained. Then on the graph paper, the frequency is plotted against the corresponding mid-value. These points are joined by straight lines. These straight lines may be extended in..

There are three methods to find mean for a frequency distribution. (i) Direct method: where x is the mid-interval f is the frequency M is the mean (ii) Short-cut method: where A = assumed mean d = x - A (iii) Step-deviation ..

Assume that the weights of 3,000 students at a university are normally distributed with mean 150 pounds and a standard deviation of 7 pounds. If 100 samples of 30 students each are obtained, then what would be the expected mean and standard deviation of the r..

To qualify in a competitive examination, candidates must score in the top 5% in the examination. The test has a mean of 200 and a standard deviation of 20. What is the lowest possible score to qualify? Assume the test scores are normally distributed. => 202.6 or 200 or..

The mean time a student spends on a computer is 4 hours per day. Assume the standard deviation is 0.7 hour. Find the percentage of students who spend more than 4.3 hours on the computer. Assume the variable is normally distributed. => 66.56% or 88.44% or 33.3..

Assume that the weights of 3,000 students at a university are normally distributed with mean 150 pounds and a standard deviation of 2.72 pounds. How many samples would you expect to find the mean between 147 and 155 pounds? => 83 or 82 or 84 or 81..

The mean weight of girls in grade 12 of school X is 125 pounds, and the standard deviation is 20 pounds. If a sample of 25 girls is selected, then what is the probability that the mean of the sample will be greater than 128 pounds? Assume the variable is normally ..