Calculating the mean Example The speeds of several cars were measured as they travelled down a road. The speeds (in mph) were 50, 53, 71, 45, 62, 50, 61, 74. Find the arithmetic mean speed of the cars

Example A cricketer scored 39, 87, 12, 0, 17, 103, 68 and 66 in eight innings. Calculate the mean score if the cricketer was not out in one of the eight innings.

Example The numbers of words on five consecutive pages of a novel are 262, 203, 182, 272, 212. What is the average number of words to a page?

Calculating the Mean from a frequency table Example A class of 22 boys were given a test in basic arithmetic. Here are their recorded scores out of 20. 11, 9, 10, 8, 11, 11, 10, 9, 16, 11, 12, 13, 11, 9, 12, 10, 14, 11, 10, 12, 13, 11. Obtain the mean score for these boys. Place the results of the 22 boys scores into the frequency table below. Mark Tally Frequency 8 9 10 11 12 13 14 15 16

Example The number of children in 25 families is as follows: 1, 2, 2, 4, 1, 1, 3, 2, 4, 3, 1, 6, 2, 3, 1, 4, 2, 5, 2, 2, 5, 1, 2, 3, 2. a) Copy and complete the table below: Number of Children (x) Tally Frequency ( f ) fx 1 2 3 4 5 6 Total b) Calculate the mean number of children per family.

Example Three coins are tossed 30 times and the number of heads per throw was recorded: Number of heads 1 2 3 Frequency 12 10 5 Work out the mean number of heads per throw

Example A six sided die was thrown 50 times. The table gives the number of times each score was obtained. Score 1 2 3 4 5 6 Frequency 7 8 10 12 Find the mean score per throw

Example Three coins are tossed 30 times and the number of heads per throw was recorded: Work out the mean number of heads per throw Number of heads 1 2 3 Frequency 12 10 5

Example The pupils in one class were asked to count the number of items in their pockets and the following frequency table was drawn up Number of items 0 – 4 5 – 9 10 – 14 15 – 19 20 – 24 Frequency 6 11 4 3 Calculate an estimate for the mean number of items in their pockets.

Example The table below shows the age distribution of 200 people in a factory Age 15 – 20 20 – 25 25 – 30 30 – 40 40 – 50 50 – 60 Frequency 18 59 63 20 25 15 Calculate an estimate for the mean age in this factory.