Econ stat cat - data analysis PDF

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data analysis...

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3.65 The following data gives the frequency distribution of number of hours spent per week playing video games by all 60 students of the 8th grade at a school Hours per week

No. of students(f ) 7 12 15 13 8 5 ∑f= 60

0 to less than 5 5 to less than 10 10 to less than 15 15 to less than 20 20 to less than 25 25 to less than 30

Mid-point (x)

X2

fX2

2.5 7.5 12.5 17.5 22.5 27.5

6.25 56.25 156.25 306.25 506.25 756.25

43.75 675 2343.75 3981.25 4050 3781.25 ∑fX2= 14875

fX 17.5 90 187.5 227.5 180 137.5 ∑fX= 840.25

Find the mean, variance and standard deviation Mean= ∑fX/∑f = 840.25/60 =14.002 Variance= (∑fX2 - ((∑fX)2/n)/ n-1 = (14875-( (840.25)2/60) 60 – 1 = 52.6779 = 52.68 Standard deviation= √variance = √52.68 =7.25809 = 7.2581

3.89

Explain the concept of the percentile rank for an observation of a data set.

In a provided set of data, the percentile rank of a given value (x) is the number of the values less than the given value of the data set divide by the number of values of the data set, then multiply by 100%...