Specimens of aluminium alloy rods are tested to determine their tensile strength. The results, in MPa, are given below.
|
357
|
339
|
342
|
341
|
348
|
332
|
336
|
341
|
346
|
346
|
|
345
|
337
|
358
|
360
|
361
|
342
|
343
|
343
|
336
|
340
|
|
352
|
352
|
346
|
345
|
348
|
341
|
340
|
344
|
353
|
350
|
|
359
|
343
|
345
|
333
|
348
|
342
|
339
|
352
|
351
|
347
|
|
344
|
341
|
340
|
347
|
336
|
339
|
360
|
345
|
353
|
359
|
|
338
|
349
|
350
|
342
|
348
|
361
|
355
|
353
|
347
|
339
|
i. Draw a frequency polygon and a cumulative frequency polygon for the data. Use the cumulative frequency polygon to estimate the median strength and the inter-quartile range of the data.
ii. Determine the mean and standard deviation of the data. What percentage of the data lies within one standard deviation of the mean value?