Biostatistics Tutorial 3

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Tutorial 3

Question 1

a) A company wishes to review its distribution operation and from its time sheet records it found that 144 vehicles were loaded in a 24 hour period. A frequency distribution table was prepared from the data as follows:

Time to load (minutes) Number of vehicles 40 up to 50 17 50 up to 60 61 60 up to 70 59 70 up to 80 7

From the above data construct :
i) a frequency histogram.
ii) a frequency polygon.
iii) a cumulative frequency curve (ogive).
iv) From your ogive estimate:

- the median loading time
- the interquatile range and quartile deviation.
- The number of vehicles loaded in under 52 minutes.

Question 2

The frequency distribution shows the times taken by 30 pupils to do their Mathematics homework. Times have been measured to the nearest minute.

Time (min) Frequency

14. 4
24. 8
34. 10
35-44 8

i) Construct a histogram of the data.
ii) Construct a polygon.
iii) Construct a less than cumulative frequency table and draw the corresponding curve. Use your curve to estimate: - the median,
- the lower and upper quartile ages, inter quartile range and quartile deviation. - the percentage of pupil spending more than 30 minutes to do their homework

Question 3

On a certain day, 500 cars were park in the parking lots of a shopping complex. The parking duration of each car (to the nearest minute) is shown in the table below.

|Time |1-20 |21-30 |31-40 |41-50 |51-60 |61-80 | |Frequency |62 |73 |90...
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