Interpreting Histograms LO: To be able to interpret histograms including finding averages

HISTOGRAMS EXAMPLE The histogram below gives information on the speed (mph) of cars on a motorway. Find the median class. Frequency = Frequency Density x Width Speed (mph) 0 ≤ x < ≤ x < ≤ x < ≤ x < 120 Frequency x x x x CF Median = 221.5th value Median class = 50 ≤ x < 80

HISTOGRAMS EXAMPLE The histogram below gives information on the speed (mph) of cars on a motorway. Find the median class. Frequency = Frequency Density x Width Speed (mph) ≤ x < Frequency CF Median =

HISTOGRAMS 1) The histogram shows the distances walked by some ramblers on the Lake District at the weekend. (a) Draw a frequency table and find the median class for the distance walked by the ramblers. (b) How many ramblers were in the sample? Distance (m) 0 ≤ x < 1 1 ≤ x < 2 2 ≤ x < 5 5 ≤ x < 7 Frequency 4 x x x x 2 6 CF ≤ x < x 3 Median = 31 2 th value = 15.5 th value Median class = 2 ≤ x < 5 Find the total of the frequency 31

2) The histogram shows the heights of plants in a greenhouse at a local garden centre. (a) Draw a frequency table and find the median class for the height of plants in the greenhouse. (b) How many plants were in the sample? Height (cm) 0 ≤ x < ≤ x < ≤ x < ≤ x < 70 Frequency 0.5 x x x x CF ≤ x < x 30 Median = th value = 27.5 th value Median class = 30 ≤ x < 45 Find the total of the frequency 54 Histogram

1) Estimate the mean for the histograms on the task. 2) Draw a frequency table and find the median class for the recorded speeds of care on a motorway. Speed (mph) 0 ≤ x < ≤ x < ≤ x < ≤ x < 120 Frequency CF Median = th value = 223 th value Median class = 50 ≤ x < 80 (a) 4.4 miles (b) 42.6 cm

The histogram shows the length of time it takes to sell houses on a estate. (b) Calculate the total number of houses that were sold. (2 marks) Frequency Density Time (months) (a) Find the median class time to sell a house on the estate. (3 marks) Time (months) 0 ≤ x < 2 2 ≤ x < 4 4 ≤ x < 8 8 ≤ x < 12 Frequency 1x2 2 7 x x x 4 32 CF ≤ x < x 12 Median = th value = 80.5 th value Median class = 8 ≤ x < 12 Find the total of the frequency 160

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