Grouped Frequency Calculating an estimate of the mean Jill Robertson

Which is the modal class? Weight61 – 6566 – 7071 – 7576 – Freq Question 1 A gardener checks the weights (in grams) of a number of tomatoes for grading purposes. Here are her results Calculate an estimate for the mean Weight61 – 6566 – 7071 – 7576 – Freq First of all we need a representative value for each group Weight61 – 6566 – 7071 – 7576 – Freq Mid-point

= m Weight61 – 6566 – 7071 – 7576 – Freq m x f Mean = = = 72.4 (3 sf) Now we need to calculate a total of the weight of tomatoes in each group 63 x x x x x We need to work out the total of our estimate of the weight and the total frequency

Why is this an estimate of the mean? Because the data has been grouped and so exact data has been lost

Calculate an estimate of the mean for this distribution Weight (Kg) Frequency Wt (Kg) F Mid-point x 1115 x 1825 x 1635 x 1145 x 555 x Mean = = = 22.9 (3 sf) m x f