Histograms Unequal Class Intervals Constructing a histogram from

  • Slides: 10
Download presentation
Histograms Unequal Class Intervals

Histograms Unequal Class Intervals

Constructing a histogram from a frequency table Example Question 1: The frequency table gives

Constructing a histogram from a frequency table Example Question 1: The frequency table gives information on the speeds (mph) of a sample of drivers using a motorway. Construct a Histogram for this data. 100 Speed freq fd 90 0 - 30 240 80 30 - 40 320 40 - 50 50 - 60 780 60 - 70 960 70 - 80 820 8 32 50 78 96 82 780/10 = 78 80 - 120 640 16 40 960/10 = 96 30 820/10 = 82 1. The class intervals are unequal so a frequency density column is needed. 20 640/40 = 16 240/30 = 8 frequency density 70 60 50 10 320/10 = 32 240 ? 0 500/10 = 50 30 2. Scale the horizontal axis. 3. Calculate frequency densities and scale the 0 10 20 30 40 50 60 70 80 90 100 110 120 vertical axis. Speed mph Cars

Constructing a histogram from a frequency table Example Question 1: The frequency table gives

Constructing a histogram from a frequency table Example Question 1: The frequency table gives information on the speeds (mph) of a sample of drivers using a motorway. Construct a Histogram for this data. 100 Speed freq fd 0 - 30 240 80 30 - 40 320 40 - 50 500 70 50 - 60 780 60 60 - 70 960 70 - 80 820 8 32 50 78 96 82 80 - 120 640 16 frequency density 90 50 Recorded Speeds of Cars on a Motorway 40 4. Draw the bars and title. 30 20 10 20 30 40 50 60 70 80 90 100 110 120 Speed mph

Example Question 2: The table shows the distance walked in miles by some ramblers

Example Question 2: The table shows the distance walked in miles by some ramblers on the Lincolnshire Wolds at the weekend. Draw a histogram for the data. 5 frequency density 4 5 1=5 3 2 1=2 5 ? 0 12 3 = 4 1 3 1=3 5 4 = 1. 25 2 1 Distance frequency fd 0 d<1 5 5 1 d<2 2 d<5 12 4 5 d<6 3 3 6 d < 10 5 1. 25 1. The class intervals are unequal so a frequency density column is needed. 2. Scale the horizontal axis. 0 1 2 3 4 5 6 7 8 Distance (Miles) 3. Calculate frequency densities 9 10 and scale the vertical axis. Ramblers

Example Question 2 The table shows the distance walked in miles by some ramblers

Example Question 2 The table shows the distance walked in miles by some ramblers on the Lincolnshire Wolds at the weekend. Draw a histogram for the data. 5 Distance Walked by Ramblers frequency density 4 3 Distance frequency fd 0 d<1 5 5 1 d<2 2 d<5 12 4 5 d<6 3 3 6 d < 10 5 1. 25 2 4. Draw in the bars and title. 1 0 1 2 3 4 5 6 7 8 Distance (Miles) 9 10

Question 3: Robert sowed some seeds in his greenhouse and measured the heights of

Question 3: Robert sowed some seeds in his greenhouse and measured the heights of the plants 3 months later. The results are shown in the table. Draw a histogram for this data. 1. 0 0. 9 0. 8 4 10 = 0. 4 frequency density 0. 7 0. 6 0. 5 0. 4 0. 3 0. 2 0. 1 20 = 1 4 ? 0 9 15 = 0. 6 10 8 25 = 0. 32 15 30 = 0. 5 height (cm) frequency fd 0 h < 10 4 0. 4 10 h < 30 20 1 30 h < 45 9 45 h < 70 8 0. 6 0. 32 70 h < 100 15 0. 5 1. The class intervals are unequal so a frequency density column is needed. 2. Scale the horizontal axis. 3. Calculate frequency densities and scale the vertical axis. 0 10 20 30 40 50 60 70 80 90 100 height (cm) Plants

Question 3: Robert sowed some seeds in his greenhouse and measured the heights of

Question 3: Robert sowed some seeds in his greenhouse and measured the heights of the plants 3 months later. The results are shown in the table. Draw a histogram for this data. 1. 0 Heights of Plants height (cm) frequency fd 0 h < 10 4 0. 8 10 h < 30 20 1 0. 7 30 h < 45 9 0. 6 45 h < 70 8 0. 32 70 h < 100 15 0. 5 frequency density 0. 9 0. 6 0. 5 0. 4 4. Draw in the bars and title. 0. 3 0. 2 0. 1 0 10 20 30 40 50 60 70 80 90 100 height (cm)

Constructing a histogram from a frequency table. Example Question 1: The frequency table gives

Constructing a histogram from a frequency table. Example Question 1: The frequency table gives information on the speeds (mph) of a sample of drivers using a motorway. Construct a Histogram for this data. Speed f 0 - 30 240 30 - 40 320 40 - 50 50 - 60 780 60 - 70 960 70 - 80 820 80 - 120 640 Worksheet 1 fd

Example Question 2 The table shows the distance walked in miles by some ramblers

Example Question 2 The table shows the distance walked in miles by some ramblers on the Lincolnshire Wolds at the weekend. Draw a histogram for the data. Distance frequency 0 d<1 5 1 d<2 7 2 d<5 12 5 d<6 3 6 d < 10 5 fd Worksheet 2

Question 3. Robert sowed some seeds in his greenhouse and measured the heights of

Question 3. Robert sowed some seeds in his greenhouse and measured the heights of the plants 3 months later. The results are shown in the table. Draw a histogram for this data. height (cm) frequency 0 h < 10 4 10 h < 30 20 30 h < 45 9 45 h < 70 8 70 h < 100 15 fd Worksheet 3