Measures of Dispersion for Grouped Data

Question 8:The data in Diagram 8 shows the weight of meat, in kg, sold each day over 40 days.36634347677168799249415266788455778658946074736256684635726880405759718192606353Diagram 8 (a) Based on the data in Diagram 9, complete Table 14 in the answer space. [ 4 marks] (b) Based on Table 2, calculate the estimated mean of the weight of meat sold over 40 days. … Read more

Question 7:Diagram below shows the marks obtained by a group of 30 students in a history test.(a) Using data in diagram above and a class interval of 5 marks, complete the table in the answer space.(b) Based on the completed table in part (a)(i) find the modal class,(ii) calculate the mean mark obtained by the … Read more

Question 5: The table below shows the frequency distribution of the time spent by 50 swimmers in the pool in a swimming practice. Time (seconds) Frequency 35 – 39 5 40 – 44 8 45 – 49 9 50 – 54 15 55 – 59 11 60 – 64 2 (a) State the modal class. … Read more

Question 3: The data below shows the mass, in kg, of 50 students. (a) Copy and complete the table below based on the data above.   (b) Based on the completed table above, (i) State the size of the class interval used in the table. (ii) Calculate the estimated mean of the mass of the … Read more

Question 1: The data below shows the age of 25 tourists who visited a tourist spot. (a) Copy and complete the table below based on the data above. (b) Based on the completed table above, (i) State the modal class. (ii) Calculate the mean age of the tourists.(c) For this part of the question, use … Read more

(A) Variance and Standard Deviation For Grouped Data (without Class Interval) Example 2: The data below shows the numbers of children of 30 families: Number of child 2 3 4 5 6 7 8 Frequency 6 8 5 3 3 3 2 Find the variance and standard deviation of the data. Solution: Mean  x ¯ … Read more

Interquartile Range of Grouped Data (without Class Interval) Example 2:  The table below shows the marks obtained by a group of Form 4 students in school mid-term science test. Determine the interquartile range of the distribution. Solution: Lower quartile, Q1 = the   1 4 ( 24 ) th observation   = the 6thobservation   = … Read more

Range of Grouped Data (with Class Interval) Example 2: The grouped frequency distribution was obtained from 100 students regarding the scores in their test shown as below. Find the range of the data. Solution: Range =midpoint of the highest class −midpoint of the lowest class Range= 35+39 2 − 5+9 2    =37−7    =30

(A) Median of Grouped Data (without Class Interval) Example 1: The frequency table shows the marks obtained by 40 students in a biology test.Solution: Median = T n + 1 2 = T 40 + 1 2 = T 20 1 2 = 60 ← ( 20 1 2 th term is 60)

7.2.1 Mode and Mean of Grouped Data (A) Modal Class The modal class of grouped data is the class interval in the frequency table with the highest frequency.   (B) Class Midpoint The class midpoint is the value of data that lies at the centre of a class. Class midpoint = Lower limit + Upper … Read more