# Biostatistics Tutorial 3

**Topics:**Median, Standard deviation, Summary statistics

**Pages:**3 (516 words)

**Published:**January 25, 2011

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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