s*****n
发帖数: 2174 | 1 是否可以t-test, yes! 前提是你认为不同人之间的血压是正态分布的.
至于你问的standard deviation, 要澄清一下, 你提到的第一个standard deviation,
是within-subject 的, 也就是每个人不同测量之间的差别. 这个和最后的t test 没关
系. 和t test有关的是每个组(不同人之间)的standard deviation, 这个依赖于你的t
test 怎么做, 是假设equal variance还是unequal variance. |
|
h******3
发帖数: 190 | 2 I looked at the hypergeometric test statistics for log-rank test. It seems
that the test won't work if the two survival curves cross each other in the
middle of the testing period.
But I am not sure, since I just started to pick up biostatistics. Thanks! |
|
A*******s
发帖数: 3942 | 3 i would also like to know the answer. seems there is no one-sample KS test,
or other distribution tests in SAS (except for normality test).
Do u need to compare NB with other alternative distributions? Then we can
use likelihood as a criterion.
I also think such tests, if exist, lack of sense in reality. How can u tell
the prob of a sample follows NB but not Poisson, zero-inflated Poisson or
zero-inflated NB? They look quite similar...
deviance/ |
|
i**4
发帖数: 4 | 4 You can probably use Kruskal-Wallis non-parametric test (multiple-group
extension of Man-WHittney test), since each ingredient distributions are not
normal. The test should be fairly powerful due to the large sample size.
This is an essentially rank-based test. |
|
e*****t
发帖数: 642 | 5 一组100个病人。在24小时内，每个小时测12次血压。想看看血压的variation（因为
variation更能体现hypertension）。文献上都是把这100个人，每小时的血压standard
deviation 求个平均值，也就是说，求 mean of every one's SD。那如果想比较第一
个小时和第二个小时mean of SD是否有统计上的差异，是用F test 还是t test？我知
道F test用来检验SD，但这里是mean of SD，不知道该用那种test。多谢 |
|
d**z
发帖数: 183 | 6 Tests for Normality
Test --Statistic--- -----p Value------
Kolmogorov-Smirnov D 0.214685 Pr > D <0.
0100
Cramer-von Mises W-Sq 30.13193 Pr > W-Sq <0.
0050
Anderson-Darling A-Sq 179.9905 Pr > A-Sq <0.
0050
The two variables (pre and post) are not normally distributed, as showed in
the above result for one of them. But the histogram... 阅读全帖 |
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w*******9
发帖数: 1433 | 7 Does Mcnemar test really test independence? Many people say when the data is
paired use Mcnemar test; otherwise choose Pearson or Fisher exact test. For
example http://yatani.jp/HCIstats/ChiSquare
What do they mean by "paired data"? Any discussion is welcome. |
|
m********8
发帖数: 161 | 8 我在尝试一种新的教学法,并准备出具新教学法的统计学证据.
有两个班级,一个班用传统的方法，另外一个用新方法。为了控制本来两个班可能的差
异，我先用传统的教学法教两个班另外一章. 然后给学生考试,
成绩统计是：
Exam 1: (Same traditional teaching method)
Class 1 Class 2
Mean 74.53 72.83 (paired t-test p-value = 0.34)
Median 71 73
Std Dev 13.7 16.98
Size 29 27
然后我教另外一章内容,一个班用传统的方法，另外一个用新方法。然后对该章进行测
试,结果如下:
Exam 2:
Class 1 Class 2
(Old method) (New method)
Mean 82.07 85... 阅读全帖 |
|
t*****8
发帖数: 157 | 9 请问比较俩组mean value, 是不是先要test数据是不是normal distribution,如果是用
ttest, 如果不是，用non parametric testing-wilcoxon-mann-whitney test？
那可不可以，assume数据是normal的，然后用t-test?
谢谢 |
|
s******h
发帖数: 539 | 10 看你样本量大不大了。大的话就用two sample z-test吧。小的话可以先做一下Shapiro
Wilk Test (univariate) 或者画个QQ plot，差不多过的去的话就two sample t-test
吧。rank test也是可以考虑的，比较robust但是power小了点。也可以考虑一下
bootstrap. |
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t*****8
发帖数: 157 | 11 有两组人，相互独立，
第一组, case,有10个人 有100次住院记录， 其中20次是离上次出院时间在5天之内，
ratio1
是 20/100；
第二组, control,有20个人 有120次住院记录， 其中30次是离上次出院时间在5天之内
， ratio2
是 30/120
test ratio1=ratio2
住院 再住院
case 100 20
control 120 30
我说用Chisquare, 但是我老板说用z test? 到底用什么test?我理解是z是assume
population variance is known,在这里只知道 sample variance,所以不能用z test，
我对吗？
谢谢 |
|
w*******9
发帖数: 1433 | 12 Google "equivalence test". The basic idea is to test whether the means of
these two groups differ by only a quantity within a certain threshold (the
alternative).
However, just like t-test, normality is needed. So if there's no way to
transform the data to "increase normality", I would suggest lz go ahead and
find some the rank based equivalence tests. |
|
w*******9
发帖数: 1433 | 13 Rank Test, K-S test, Nonparametric Likelihood Ratio Test. There are many
variants of rank tests, depending on the weight used. It's possible to look
at the shape of the distribution to choose a (potentially) best weight. |
|
p*****n
发帖数: 265 | 14 weiwei同学，谢谢你的解释，恩
我现在对两种test更明白一些了。我想两个test都试一下好了，反正命令很简单，在R
里面运行很快。
我需要在R里面随机把whole data分两份，然后做两种test。这样进行10次，如果每次p
value都很大（也就是两部分分布差不多），是不是可以说，这组数据的分布没有必要
分组呢？
我希望得出的结论是没有必要分组，就用whole data来得出分布。
谢谢啦！
median |
|
P**********3
发帖数: 77 | 15 工作中的问题。信用卡loss rate的两个重要metrics就是unit charge off（坏帐）
rate和dollar charge off rate. 前一个＝# charge-off/# accounts, 第二个 = $
charge off/$ balance
比如1000个account charge off了10个，unit rate就是1%, 这1000个account的total
balance是$1M, 那10个account charge off的balance是$20K,那么dollar rate就是2%.
现在有test和control group,要比较两个group的两年unit charge off rate和dollar
charge off rate是否一样。
unit charge off rate比较简单，可以用chi-square test. dollar charge off rate
我觉得应该不能用chi-square test吧。大家觉得应该如何Test？thanks. |
|
l****s
发帖数: 6 | 16 高手们都不愿意回答你这样的入门问题。
每一行的pos是不是唯一的？如果是，可以就下面loop代码。如果不是，就稍改一下t.
test那行。看你数据结构，不象是配对t-test，但如果是，也稍改一下t.test那一行。
假设你读入的数据对象名为myData。
#++++++++++++++++++++++++++++++++++++++++
output<-vector("list",length(myData$pos))
n=0
for(ii in unique(myData$pos))
{
n=n+1
indx<-which(myData$pos==ii)
output[n]<-t.test(myData[ind,2:5],myData[ind,6:9])
} |
|
j*****y
发帖数: 26 | 17 工业界，对A/B test有明确定义么？
大部分时候A/B test就是问“两个group某种metric有没有什么差别”，或者“有没有
treatment effect" 吧？
至于用什么model，Anova，还是regression,还是甚至一些高大上的模型，都属于A/B
test的范畴吧？ |
|
s******y
发帖数: 522 | 18 像microarray和RNA-seq, 会产生成千上万个t-test statistics或者likelihood ratio
test statics
我现在想要找一个非genetic的数据也能产生大量的likelihood ratio test statics
或者有现成的test statistics直接拿来用最好
查文献好像只有imaging data符合要求, 但是我对imaging data的处理毫无经验
希望板上大牛能指点一些方向 |
|
S****a
发帖数: 45 | 19 【 以下文字转载自 test 讨论区 】
发信人: SeanMa (肖恩·马，蘑菇有毒), 信区: test
标 题: test
发信站: BBS 未名空间站 (Fri Aug 14 00:28:13 2015, 美东)
我来了
注册三天后才能发帖可是憋死我了
至少test能让新注册用户发发贴吧 |
|
i**********a
发帖数: 149 | 20 看见很多DS职位上面都要求会A/B testing，以前以为A/B testing很简单，类似于做个
t-test什么的。但是在实际business的应用下面好像有很多很复杂的变种，然后面试的
时候问到了也不会回答
想问下大家伙有A/B testing比较系统地课或者online resource吗可以自己学习下的马？
谢谢！ |
|
m******n
发帖数: 453 | 21 training data一般都需要standardized
建立好模型之后
那么这时候去predict test data
test data也需要一样的标准化处理吗
是不是用原始数据的test data
可是，如果对test data也进行scale的话
predict出来的y，也是标准化的值啊，怎样recover到原来的值去 |
|
E**********e
发帖数: 1736 | 22 4万就用来建模啊，四万再随即分成70/30比例，这两个就是training/test，然后
iteration30次。不过这个过程叫做sampling with/without replacement, 前者也看作
bootstrapping. CV 是把4万随机分成5份或者10份额, 留一份做test，其余的training
你的model. 然后轮换。总共跑k次，这叫做k-fold CV。如果在套个loop，就叫做
repeated -fold CV, 这个其实能提供最接近unbiased估计值和 小的variance.
总之，CV是用来test 你的modeling procedure是否可行。最终应该用1万的数据来检测
你的model performance,而不是 trainging/test 的数据。 你可以自己实验一下，4万
数据用来选最后的20左右的变量，然后CV,你得到的metric 必然偏高，这就是因为你偷
看了数据，带入了BIASE。
对了5万的数据已经挺多了。
：看了几遍没看懂。 能不能说写具体的？ 比如说，你拿到手5万行数据集（也就是五万
：客户），100个... 阅读全帖 |
|
E**********e
发帖数: 1736 | 23 你看看我原来的帖子， 这也是我的问题， 接机请教达人。
CV 和modeling performance的 evaluation 应该是独立的。 CV 只是用了检测你的
modeling procedure 合不合理。 用CV里的test data的 performance看model 是不是
好要小心。如果40000数据先用来选预测力强的变量，然后用这40000的数据进入 CV，
你得到的在test 上的结果就是biased， 一般来说要好一点。
我的折中就是用40000来预选变量， 但是评价model 好坏不要用40000里的test 数据。
而是没有碰过的10000数据。 还有，这个10000可不是随机的， 一般是最近一段时间
的数据。 如果是随机的， 也是没有意义的，它其实就是约等于test 数据。
以上40000只是个例子。你要是有10000以上的training 数据， 你可以再选出3000 用
来预选变量， 然后不用。 剩下的7000用来CV。 因为3000的数据基本上可以把变量的
预测力给显示出来。
问题是很多小公司只有5,6000数据。 这就比较challenging... 阅读全帖 |
|
w*******y
发帖数: 60932 | 24 Earn 2500 Bonus Points a $50 Value
Premier Silver members only: Test-drive the new Ford Edge featuring SYNC
with My Ford Touch technology at a Ford dealer near you anytime from
November 22 December 19, 2010, and you'll earn 2500 Reward Zoneprogram
bonus points. Offer quantities are limited, so register now.
Just sign in on rewardzone.com and select Offers and Partners and then
Featured Offers.
I'm not sure if you need to do an actual test drive as it seems all you need
is the dealer code from ... 阅读全帖 |
|
w*******y
发帖数: 60932 | 25 LOWEST COST BLOOD TESTS
Patients needing lab work can go to the medical society's website and click
on the big yellow box in the middle of the page. From there they choose the
tests their doctor says they need , give the doctor's fax number, pay with a
credit card and print out the order. They then take the order to any
LabCorp location in 47 states and have the work done. Results are sent
securely to the patient and the doctor, often within 24 hours.
"It's like using Amazon.com to buy your lab ... 阅读全帖 |
|
w*******y
发帖数: 60932 | 26 Link:
http://2011optimatestdriveoffer.cloudapp.net/
Test-drive the all-new 2011 Kia Optima between February 3, 2011, and March
31, 2011, and theyll thank you with a $25 prepaid card.
PREPAID CARD DISCLOSURE: The Visa prepaid card is not redeemable for cash or
usable at any ATM. The plastic Visa prepaid card itself expires 12 months
after issuance; provided, however, the funds available on the prepaid card
do not expire. If funds remain on the card after expiration of the prepaid
card, please con... 阅读全帖 |
|
w*******y
发帖数: 60932 | 27 A new program has just been added to the dashboard: Xbox LIVE Labs. The
first "experiment" is a series of network tests. After each test has
completed, an avatar award will immediately unlock:
30 minutes - Lab Technician - Lab Coat
One hour - Senior Research Analyst - Brain Helmet
Six hours - Mad "360" Scientist - Crazy Wig
The testing app can be downloaded and accessed from the My Community tab.
If the program is terminated before all three tests have completed, you will
need to start over from... 阅读全帖 |
|
w*******y
发帖数: 60932 | 28 Link:
http://www.khanacademy.org/
Free Step By Step Video's On Math, Science, Humanities & Other, Test Prep's
Learn almost anything for free.
With a library of over 2,600 videos covering everything from arithmetic to
physics, finance, and history and 207 practice exercises, we're on a mission
to help you learn what you want, when you want, at your own pace.
Learn Anything to Math, Science, Humanities & Other, Test Prep's
Math
Too Basic Math..
Arithmetic
Developmental Math
Developmental Math 1
De... 阅读全帖 |
|
m*********g
发帖数: 11102 | 29 http://edition.cnn.com/2006/WORLD/asiapcf/10/08/nkorea.tests.ap/index.html
North Korea may drop nuclear test
POSTED: 1302 GMT (2102 HKT), October 8, 2006
SEOUL, South Korea (AP) -- North Korea informed China it may drop its plan t
o test its first atomic bomb if the United States holds bilateral talks with
the communist country, a former South Korean lawmaker said Sunday.
The North also denied speculation that its nuclear test was imminent and sai
d the regime has not raised the alert level of t |
|
|
c**i
发帖数: 6973 | 31 Press release: THAAD Weapon System Achieves Intercept of Two Targets at
Pacific Missile Range Facility. Lockheed Martin, Oct 5, 2011
http://www.lockheedmartin.com/news
/press_releases/2011/MFC_100511_THAADAchievesIntercept.html
("During the mission, the first THAAD missile intercepted an air-launched
short-range ballistic missile target. The second THAAD missile intercepted a
sea-launched short-range ballistic missile target a short time later. Since
2005, the program has completed 12 flight tes... 阅读全帖 |
|
y**o
发帖数: 8897 | 32 【 以下文字转载自 Dreamer 讨论区 】
发信人: Dreamer (不要问我从哪里来), 信区: Dreamer
标 题: Pap test 把处女膜给捅了 = =
发信站: BBS 未名空间站 (Fri Jan 20 21:49:07 2012, 美东)
我知道这件事情很坑爹，但是实在心里障碍了要上来吼一声。第一次匿名发文，匿不成
功的话就删吧。
来美国几年，第一次去做年度生理健康检查。我之前没有做过，也不知道具体检查的项
目是什么，只知道是查女性健康。
其中有个Pap test （Papanicolaou test，宫颈抹片检查），检查宫颈癌的，当时医生
说了是查癌症的，并且说过了18岁都要做。我听说她是要从宫颈取样，就问她处女能不
能做，她说能呀，好多女生没有过性经验，包括她女儿在内，都是过了18岁就做测试。
当时我就信了，然后取样的时候觉得很痛，取样完之后有血迹，……后来回家查，发现
这个测试会损伤处女膜。
我觉得坑爹了！我连男朋友都没有过呢！虽然不是说有处女情结什么的，但是只是觉得
自己亏大了，哭……
现在请教几个问题。
1，一般来说，OOXX时候处女膜破裂，会流多... 阅读全帖 |
|
g**1
发帖数: 10330 | 33 http://nypost.com/2014/10/27/5-year-old-boy-being-tested-for-eb
5-year-old boy tested for Ebola in NYC after return from Africa
By Larry Celona and Kenneth GargerOctober 27, 2014 | 3:30am
Modal Trigger
5-year-old boy tested for Ebola in NYC after return from Africa
Bellevue Hospital
Photo: AP
A 5-year-old boy who just returned from West Africa was transported to
Bellevue Hospital Sunday with possible Ebola symptoms, according to law-
enforcement sources.
The child was vomiting and had a 103-degr... 阅读全帖 |
|
m***a
发帖数: 13878 | 34 CAPE CANAVERAL, Fla. (Reuters) - Two years after unveiling plans for a
futuristic, high-speed Hyperloop transportation system, technology
entrepreneur Elon Musk announced plans for building a test track in southern
California and a competition for prototype pods, documents obtained by
Reuters show.
As described in Musk's 57-page white paper, the solar-powered Hyperloop
would shoot passengers in enclosed capsules through low-pressure steel tubes
at up to 800 mph (1,288 kph).
Several companies sub... 阅读全帖 |
|
|
d*****u
发帖数: 17243 | 36 一下给印度送去15例。
意大利的杀伤力跟武汉差不多了。
The All India Institute Of Medical Sciences (AIIMS) said 15 Italian tourists
have tested positive for coronavirus on Wednesday. The group of Italian
tourists has been quarantined at an ITBP facility in New Delhi.
The development comes a day after an Italian tourist in Jaipur was tested
positive for coronavirus and his wife showed initial symptoms of the virus.
The Italian couple was part of a tourist group touring Rajasthan.
Now, with 15 more Italian tourists, who wer... 阅读全帖 |
|
发帖数: 1 | 37 瓮里6563啊！啧啧啧，啧啧啧，十个字。
Despite vows to drastically expand the coronavirus testing regime, federal
and state public health authorities have tested only 6,563 people for the
coronavirus as of Tuesday morning, according to the Centers for Disease
Control and Prevention and numbers provided by all 50 states.
https://www.huffpost.com/entry/americans-tested-for-coronavirus-so-far_n_
5e67f271c5b60557280cede6 |
|
T*******e
发帖数: 4110 | 38 How one woman fought to get her husband tested while her state was applauded
for having no coronavirus
(CNN)Carolyn Vigil was lying in bed next to her husband when she first saw
the meme. It noted West Virginia had no reported cases of coronavirus, and
jokingly pleaded for its people to hang on.
She remembers it so well because it's the day her husband James began to
feel sick in their Shepherdstown home in the West Virginia panhandle.
Her husband was sick from Covid-19. But her "coronavirus-fre... 阅读全帖 |
|
r*****g
发帖数: 9999 | 39 尼玛，这就是我图稳住疫情的秘诀吗？80岁老太太都轮不到被测试。
https://www.reddit.com/r/CoronavirusWA/comments/fodjv8/tests/
Wtf are tests? People act like meh. But WE F*CKING NEED TEST PEOPLE. This
should have already started a vast revolution in and of itself. Now where I
’m the hell can i find a provider in Clark County as no one seems to be
able to figure it out as my 80 year old mother in law is OBVIOUSLY very sick
has temperature and a cough that’s would chill you immediately. Now WHO
THE HELL CAN STEP UP |
|
E*V
发帖数: 17544 | 40 【 以下文字转载自 Military 讨论区 】
发信人: EUV (奶特都是卖国贼), 信区: Military
标 题: China Test of Stealth Fighter Is Reported(nyt)
发信站: BBS 未名空间站 (Tue Jan 11 10:08:22 2011, 美东)
BEIJING — In a show of force that seemed aimed at the United States and
visiting Defense Secretary Robert M. Gates, China apparently conducted the
first test-flight of its new stealth fighter jet on Tuesday, only hours
before Mr. Gates was to meet with President Hu Jintao.
....
Mr. Gates said he directly asked Mr. Hu why it was conducted dur... 阅读全帖 |
|
z*****1
发帖数: 130 | 41 LOS ANGELES (AFP) – A robotic, bat-winged bomber designed to take off from
a US aircraft carrier has passed its first test in a debut flight in
California, the US Navy said.
The X-47B jet, which looks like a smaller version of the B-2 stealth bomber,
stayed in the air for 29 minutes and climbed to 5,000 feet in a test flight
on Friday at Edwards Air Force Base, according to the Navy and defense
contractor Northrop Grumman.
Military leaders see the plane as part of a new generation of drones that... 阅读全帖 |
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b**u
发帖数: 1206 | 42 【 以下文字转载自 NewYork 讨论区 】
发信人: LXJSmonk (紫色心情的 LXJS NYC_monk), 信区: NewYork
标 题: HIV TEST归来... (T_T)
发信站: BBS 未名空间站 (Tue Aug 10 20:08:19 2010, 美东)
发信人: major2 (主要的二), 信区: Rainbow
标 题: HIV TEST归来... (T_T)
发信站: BBS 未名空间站 (Tue Aug 10 19:34:12 2010, 美东)
先说结果.Negative.
然后谢谢之前在帖里的几位,和尚,隆冬盖,jumper,crush,jeremy,江湖郎中,等等等等.
你们的解释让我不那么担心也鼓起勇气去做了.
下面说说经过.
今天中午在HOLLYWOOD那边做的.啊... (T_T) HOLLYWOOD真是个很多帅哥的地方...
这是个免费TEST的LOCATION,做的是口腔组织测试,20分钟就能知道结果.
SIGN IN之后坐下来等.一个很NICE的小墨妹妹叫我进房间然后开始跟我谈.
MM:之前有来过吗?
我:没有,第一次. |
|
g********2
发帖数: 6571 | 43 DONALD TRUMP Challenges #SickHillary to Drug Test Before Debate!
Jim Hoft Oct 15th, 2016 12:58 pm 54 Comments
hillary stairs
Donald Trump spoke to a HUGE audience today in New Hampshire.
The GOP nominee questioned why Hillary Clinton needs so many days off from
campaigning each month?
Hillary is taking the week off before the third debate knowing the Democrat
mainstream media will do her bidding while she’s resting.
Donald Trump challenged Sick Hillary to a drug test before the third and
final d... 阅读全帖 |
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n******g
发帖数: 17225 | 44 New York’s top Asian-American elected official slammed Mayor de Blasio for
proposing to eliminate the admission test at the city’s eight prestigious
public high schools without input from Asian-American leaders and parents.
“The mayor and chancellor failed to convene a meeting of all relevant
stakeholders, including the City’s AAPI [Asian American and Pacific
Islanders] elected officials, before they unveiled a proposal that seeks to
dismantle how the City’s most successful high schools operate,... 阅读全帖 |
|
I****e
发帖数: 7742 | 45 According to reports, Toyota's chief test driver, 67-year-old Hiromu Naruse,
has died in a crash on highway 410 near the famed Nürburgring race track
in Germany. He was driving the recently spied Lexus LFA Nürburgring Edition
(above) at the time of the accident, and reports say he veered into the
oncoming lane and collided head-on with two others test drivers in a BMW.
The two BMW test drivers survived the crash, though one is reportedly still
in critical condition.
http://www.autoblog.com/2010/ |
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i****a
发帖数: 36252 | 46 结果截然不同 = 没用?
"The revamped system provides an overall ratings score to help make
comparing vehicle safety easier. The score will combine findings from the
frontal crash test and side crash test, as well as a new side-impact
oblique pole and rollover test." |
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c********a
发帖数: 2829 | 47 I heard if you retire a car that failed smog test to a government junk yard,
you can get $1000.
If your car passed smog test, you can get only a few hundred.
Is that true?
Is it hard to do some extra work on a car so that it will fail smog test for
sure? |
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y***n
发帖数: 2318 | 48 【 以下文字转载自 NewJersey 讨论区 】
发信人: yeson (快乐着并幸福着...), 信区: NewJersey
标 题: How soon to get a road test date?
发信站: BBS 未名空间站 (Sun Apr 17 21:48:20 2011, 美东)
One friend needs to schedule a road test in May, any idea how many days in
advance to get a test date? Hopefully one-day advance or even the same day.
Please advise, thanks! |
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m*****t
发帖数: 345 | 49 车是2005年的FOCUS，十万迈，车况很好。
目前在北弗吉尼亚地区，VA emission test是可以顺利通过的。
本来是想运车到加州
结果在dealer那保养车的时候发现这辆车没有certified for sale in California
也就是说不保证能过加州的smog test
求教版上加州的牛人们：
加州smog test严格到什么程度？
没有certified for sale in CA 有多大几率可以过关？
有没有详细标准可以在外州对照测试一下？
谢谢。 |
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a*******e
发帖数: 463 | 50 前几天收到一封email，是Subaru [A*******[email protected]]发来的，信里说：
Schedule a Subaru Legacy test-drive† by May 21, 2012 and receive a
$50 Gas Card‡.
我想问问，这个靠谱吗？有做过这样的test-drive的吗？
update：去了，很痛快的就给油卡了，都没用test drive。估计dealer觉得费事吧，哈 |
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