Question

The Los Angeles County Metropolitan Transportation Authority (branded as LA Metro) is an agency that operates public transportation in the Los Angeles metropolitan area. One of the key to satisfying bus riders is that the busses run on schedule. One important part of this requires that the variation in travel time for the bus route to be controlled. Suppose on one particular bus route, LA Metro wants the standard deviation in travel time to be 2 minutes. To test this, a random sample of 12 trips is selected. 4. State the appropriate null and alternative hypotheses. 5. Assuming that Metro wishes to test the mull hypothesis in part of using a significance level equal to 0.05, what conclusion should be reached if the sample standard deviation is 1.4 minutes?

Answer 1

Claim: The standard deviation in travel time to be 2 minutes.

Sample size = n = 12

Sample standard deviation = s = 1.4

The null and alternative hypothesis is

Test statistic is

Level of significance = 0.05

Degrees of freedom = n - 1 = 12 - 1 = 11

Critical value = 19.675

( From chi-square table)

Test statistic < critical value we fail to reject null hypothesis.

Conclusion: The standard deviation in travel time to be 2 minutes.