Question

w w ,xes, and improvements, choose Check for Updates. 8. Greyhound advertises that their buses offer free wifi, outlets, and more leg room than other bus companies. They also advertise that their new Express service (marked with the "e" logo) is faster than all competitors. While the average time of travel between New York to Atlanta for all other bus companies is 11.5 hours (o = 0.25 hours), Greyhound claims that the Express service can get customers between cities quicker, and for a lesser price. To lend evidence to this claim, the analysts at Greyhound collect a random sample of 40 NY-ATL trips and record the time of travel (x = 9.75 hours, s = 0.15 hours). The analysts want to be confident, so they use a stricter alpha of 0.01. Test their claim. a. Which inference test would you choose? Why? b. Is this a one tail or two tailed test? How do you know? C. Evaluate the hypothesis using the five steps of NHST. 1. State the research question 2. Define the parameter of interest and alpha level. 3. Write the null and alternate hypotheses. Additionally, interpret the hypotheses. 4. Evaluate Ho using the sampling distribution. Fill in the critical region(s), critical value(s), mean, sd, and observed test statistic on the normal curve. Page 1 of 3 742 words CX English (United States)

Answer 1

a)

we will use a one sample z test as the population standard deviation is given.

b)

It is one tailed test. as it is given it is directional.

c) 1. The average time of travel between New York to Atlanta is less than 11.5 hpurs

2. Parameter of interest =9.75

α = 0.01

x̅ = 9.75, σ = 0.25, n = 40

Null and Alternative hypothesis:

Ho : µ ≥ 11.5 ; H1 : µ < 11.5

Critical value :

Left tailed critical value, z crit = NORM.S.INV(0.01) = -2.326

Reject Ho if z < -2.326

Test statistic:

z = (x̅- µ)/(σ/√n) = (9.75 - 11.5)/(0.25/√40) = -44.2719

Decision:

Reject the null hypothesis.