Change 35/7 to mixed or whole number
2 answers:
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Answer:
The standard deviation of tire life does exceed 3000 km
Step-by-step explanation:
This is a Chi-Square Hypothesis Test for the Standard Deviation, here we have
so, this is an upper one-tailed test.
The <em>test statistic</em> is
where
<em>n = 10 is the sample size</em>
<em>s = sample standard deviation</em>
= population standard deviation
we would reject the null hypothesis if
where
is the critical value corresponding to the level of significance with n-1 degrees of freedom.
we can use either a table or a spreadsheet to compute this value.
In Excel use
CHISQ.INV(0.05,9)
In OpenOffice Calc use
CHISQINV(0.05;9)
and we get this value equals 3.3251
Working out our T statistic
Since T > 3.3251 we reject the null and conclude that the standard deviation of tire life exceeds 3000 km.