Statistics

2009-11-25 8:52 pm
The manager of a service station is in the process of analyzing the number of times car owners change the oil in their cars. She believes that the average motorist changes his or her car's oil less frequently than recommended by the owner's manual which is two times per year. In a preliminary survey she asked 15 cars owners how many times they changed their car's oil in the last 12 months. The result are listed below :

1 1 2 1 2
2 0 1 0 1
2 3 1 3 0

Q1, The value of the test statistic in this problem is approximately
equal to ____ ?
Answer should between two and four decimal places. e.g. 1.23, 1.234, 1.2345

Q2. What would be your decision if a hypothesis test was conducted on this problem with the null hypothesis given H0 : u is greater or qual to 2 and the alternate hypothesis given as H1 is smaller than 2 ?

a) Reject H0 at the 10%, 5% and 1% level of significance
b) Reject H0 at the 10% and 5% level of significance but do not reject H0 at
the 1% level of significance
c) Reject H0 at the 10% level of significance but do not reject H0 at the 5%
or 1% level of significance
d) Do not reject H0 at either the 10%, 5% or 1% level of significance
更新1:

please ignore &#39 in the first paragraph, it is only a punctuation.

回答 (1)

2009-11-26 3:13 am
✔ 最佳答案
Q1 The value of the test statistic in this problem is approximately
equal to (1+1+2+1+...+0)/15=20/15=1.33

Q2 Approximately, the standard deviation is 0.9428. So from the statistic
√15(1.33-2)/0.9428=-2.7523. We conclude that reject H0 at the 10%, 5% and 1% level of significance


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