Question

1. The following table shows the data for a number of companies with the largest oil refining capacity in the world according to the Petroleum Intelligence Weekly. Use these sample data and answer the questions:

Company	Capacity (10,000 Barrels per day)
Exxon	427
Royal Dutch/Shell	379
China Petroleum Crop.	286
Petroleos de Venezuela	243
Saudi Arabian Oil Co.	197
British Petroleum	196
Chevron	166
Petrobas	154
Texaco	153
Petroleos Mexicanos (Pemex)	152
National Iranian Oil Co.	109

1. Calculate the mean, median [2 marks]
2. Calculate the range, interquartile range, and sample variance. [5 marks]
3. Calculate the coefficient of variation and coefficient of skewness [3 marks]

Answer 1

F G I K L N a. Mean Median 223.82 196 b. Capacity 427 379 286 243 197 196 166 154 153 152 109 Range Q1 Q3 Interquartile Range Sample variance 318 153.5 264.5 111 10266.56 c. standard deviation of population 96.61 Sample standard deviation Coefficient fo variation 101.32 45.27% coefficient of skewness 0.8638

Formula Reference:

F G H - . K L a. Mean Median =AVERAGE(G4:G14) =MEDIAN($G$4:$G$14) b. Capacity 427 379 286 243 197 196 166 154 153 152 109 Range Q1 Q3 Interquartile Range Sample variance =MAX(G4:G14)-MIN(G4:G14) =QUARTILE(G4:G14,1) =QUARTILE(G4:G14,3) =K9-K8 =VAR(G4G14) c. standard deviation of population ESTDEV.P(G4:14) Sample standard deviation Coefficient fo variation ESTDEV(G4:G14) =(K15/K4)*100% coefficient of skewness =3*(K4-K5)/K13

coefficient of skewness formula:

=3*( AVERAGE(B2:B29)-MEDIAN(B2:B29) ) / STDEV.P(B2:B29)”

coefficient of variation formula:

=(standard deviation / average)*100%

interquartile range = q3 - q1