A statistics instructor asks each student in his classes to report how much the student spent on textbooks for the semester. The figures reported by students are shown below. 725 735 555 420 385 480...

A statistics instructor asks each student in his classes to report how much the student spent on textbooks for the semester.  The figures reported by students are shown below.

725	735	555	420	385	480	505	270	405
285	585	450	515	560	500	395	545	595
365	455	505	345	555	485	560	475	520
455	355	590	550	495	505	505	495	465
370	355	480	385	515	605	480	410	485
560	475	350	465	435	455	380	320	535
565	520	510	495	485	650	490	295	555
540	565	490	570	380	610	600	390	375
390	335	525	445	540	490	485	555	440
560	405	590	520	470	560	510	340	385
585	635	415	455	590	385	505	510	545
405	470	560	495	515	495	595	565	615
470	680	465	470	310	470	505	465	375
360	650	460	560	500	375	500	370	415
490	440	470	525	535	640	385	475	425
595	505	365	485	495	390	380	585	690

Extracted text: The instructor takes a random sample of size from the population data and obtains the following sample data: 405 385 495 385 555 470 1 The sample variance is: a 3,487.66 b 3986.81 4,305.75 d 4,784.17