Question

The mean of the following frequency distribution is 25. Find the value of f.

Find the mean of the following data using assumed mean method :

The weights (in kg) of 50 wild animals of a National Park were recorded and the following data was obtained : | Weight (in kg) | Number of animals | |----------------|------------------| | 100 – 110 | 4 | | 110 – 120 | 12 | | 120 – 130 | 23 | | 130 – 140 | 8 | | 140 – 150 | 3 | Find the mean weight (in kg) of animals, using assumed mean method.

In calculating the mean of grouped data, grouped in classes of equal width, we may use the formula x̄ = a + Σfᵢdᵢ/Σfᵢ where a is the assumed mean. a must be one of the mid-points of the classes. Is the last statement correct? Justify your answer.