Statistics
posted by Alisha .
A comparison is made between two bus lines to determine if arrival times of their regular buses from Denver to Durango are off schedule by the same amount of time. For 51 randomly selected runs, bus line A was observed to be off schedule by an average time of 53 minutes, with a standard deviation of 19 minutes. For 60 randomly selected runs, bus line B was observed to be off schedule an average of 62 minutes, with a standard deviation of 15 minutes. Do the data indicate a significant difference in average off schedule times? Use a 5% level of significance.

Z = (mean1  mean2)/standard error (SE) of difference between means
SEdiff = √(SEmean1^2 + SEmean2^2)
SEm = SD/√n
If only one SD is provided, you can use just that to determine SEdiff.
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to the Z score.
Respond to this Question
Similar Questions

funny question
in a circular road there is a fixed point from which two buses move in clockwise and anticlockwise. in every after 20 mins there is a bus moving in either direction.a man came to the point randomly and picked up the bus that came first.he … 
psych
Given the following problem: Pretend that you are a bus driver. You begin the day with an empty bus. At the first stop, you let on 10 passengers. At your second stop, 4 people get off the bus, and 12 people on. At your third stop, … 
algebra help please
A bus leaves a station at 1p.m. traveling west at an average rate of 44 mi/h.one hour later a second bus leaves the same station traveling east at a rate of 48mi/h. At what time will the two buses be 274 miles apart I know that I am … 
Algebra
The bus stations in Trawlwy and Fenton are 220 miles apart. A bus left Trawley for Fenton at 9:00am. Traveling at 40 miles per hour. One hour later, an express bus left Fenton for Trawley traveling along the same road at 50 miles per … 
Math
The bus stations in Trawlwy and Fenton are 220 miles apart. A bus left Trawley for Fenton at 9:00am. Traveling at 40 miles per hour. One hour later, an express bus left Fenton for Trawley traveling along the same road at 50 miles per … 
Algebra
The bus stations in Trawlwy and Fenton are 220 miles apart. A bus left Trawley for Fenton at 9:00am. Traveling at 40 miles per hour. One hour later, an express bus left Fenton for Trawley traveling along the same road at 50 miles per … 
mathematics
Two towns T and S are 300km apart, two buses A and B started from town T at the same time moving towards town S, Bus B traveling at speed 10km/h greater than bus A and reached S 1 1/4 hours earlier. Find the average speed of A? 
Statistics
Assume a study of 500 randomly selected school bus routes revealed 480 arrived on time. Is it significant for a school bus to arrive late? 
Physics  Collisions
A big toy school bus rearends a small toy school bus initially at rest. The bigger bus is several times heavier than the smaller one. Which of the following statements are true if the collision is totally inelastic? 
math
two buses start from the same bus stand at 8am . one travels at 40km/h and the other at 50km/h . the second bus reaches the next stop at 10am. how much later will the first bus arrive?