econ2202 -A 得近来一下贝

[Stifler]

any1 has clue on question #1 and 2
since our TA said using F critical value solve both question out..

i was using chi-square 1st time, but he said its incorrect

 

[Stifler]

1. An automative part must be machined to close tolerances to be acceptable to customers. Production specifications call for a maximum variance in the lengths of the parts of 0.0004. Suppose the sample variance for 30 parts turns out to be s2 = 0.0005. Using α = 0.05, test to see whether the population variance specification is being violated.

 

[Stifler]

1. The Folbert 100-watt light bulb is known to last an average of 3.0 years, with σ = 1 (year). A sample of five of Folbert’s new improved 100-watt bulbs resulted in lives of 1.3, 4.1, 7.8, 3.4, and 2.9 years. Test if the new variance is larger than the old variance with α = 0.05. Assume that the distribution of the life of all 100-watt bulbs is normal. Show your decision rule.

 

[Stifler]

太难了

 

[Stifler]

用f-critical的方法作

 

[不想独自快乐]

用F value不可能做得出来的阿

 

[Stifler]

en, problem solved out..

hehe..

 

[不想独自快乐]

TA回信了说可以用chi-square

 

[Stifler]

TNX

 

[~鸡蛋壳~]

把我的也写了

 

[Stifler]

最初由 ～全世界失眠～ 发布
把我的也写了

me, out of mind...