Report on Maths Statistics and Probability
Added on 2020-06-05
10 Pages1763 Words41 Views
Maths - Statistics andProbability
classinterval mid-Value ( x ) tallyfrequency ( f ) Cummulative frequencyf xx -x(x - x)2f (x - x)20-1051414703.75 14.06196.84 10-2015173125513.75 189.06 3214.02 20-30251849450 23.75 564.06 10153.0830-4035116038533.75 1139.06 12529.66Total8060Question 1 i) calculate the mean, correct to one decimal place Mean of grouped data = sum of x/ sum of frequency= 80/60= 1.33 ii) calculate the standard deviation, to the nearest whole number.For 5; 5- 1.33 = 3.67; 3.67*3.67 = 13.468For 15; 15- 1.33 = 13.67; 186.86For 25; 23.67; 560.26For 35; 33.67; 1133.6c) i) Add a cumulative frequency column to the table, and complete it.classinterval mid-Value ( x ) tallyfrequency ( f ) Cummulative frequencyf xx -x(x - x)2f (x - x)20-1051414703.75 14.06196.84 10-2015173125513.75 189.06 3214.02 20-30251849450 23.75 564.06 10153.0830-4035116038533.75 1139.06 12529.66
Total8060 ii) Use this column to help you find approximations for the 1st and 3rd quartiles, and thus...For calculating the 1st and 3rd quartiles, we have to follow the steps below:1st QR = (n + 1) / 4= ( 40 + 1) /4= 10.252nd QR = (n + 1) / 4 *2= 10.25 * 2= 20.5We also have to find the 3rd QR for calculating the interquartile range,3rd QR = (n + 1) / 4 *3= 10.25 *3= 30.75 iii) calculate the interquartile range.IQR = Q3 - Q1 = 30.75-10.25 = 20.5d) i) Construct a cumulative frequency polygon (you may choose to overlay it with an ogive).
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