Reference no: EM132344088
A report states that the cost of repairing a hybrid vehicle is falling even while typical repairs on conventional vehicles are getting more expensive. The most common hybrid? repair, replacing the hybrid inverter? assembly, had a mean repair cost of ?$3,927 in 2012. Industry experts suspect that the cost will continue to decrease given the increase in the number of technicians who have gained expertise on fixing? gas-electric engines in recent months. Suppose a sample of 100 hybrid inverter assembly repairs completed in the last month was selected. The sample mean repair cost was ?$3,880 with the sample standard deviation of ?400. Complete parts? (a) and? (b) below.
Is there evidence that the population mean cost is less than ?$3,927?? ?(Use a 0.01 level of? significance.)
H0: _____
H1: _____
Find the test statistic for this hypothesis test.
tStat = __
The critical? value(s) for the test statistic? is(are) ___
Is there sufficient evidence to reject the null hypothesis using α=00.01??
A Do not reject the null hypothesis. There is insufficient evidence at the 0.01 level of significance that the population mean cost is greater than ?$3,927.
B Reject the null hypothesis. There is sufficient evidence at the 0.01 level of significance that the population mean cost is less than ?$3,927
C Reject the null hypothesis. There is sufficient evidence at the 0.01 level of significance that the population mean cost is greater than ?$3,927.
D Do not reject the null hypothesis. There is insufficient evidence at the 0.01 level of significance that the population mean cost is less than ?$3,927.
Determine the? p-value and interpret its meaning.
The? p-value is __
What does this? p-value mean given the results of part? (a)?
A The? p-value is the probability that the actual mean cost is ?$3,880 or less.
B The? p-value is the probability that the actual mean cost is ?$3,927 or less given the sample mean cost is ?$3,880.
C The? p-value is the probability of getting a sample mean cost of ?$3,880 or less if the actual mean cost is ?$3,927.
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