Test 02 9-10 Confidence interval hypothesis test • Name:

1. For the following curves A, B, and C determine the mean µ and the standard deviation σ:

2. Using global positioning satellite systems, the length of lane four at the Pohnpei state track facility was measured nine times. Use the data above to determine the sample mean x and the sample standard deviation sx. Use this data to calculate a 95% confidence interval for the population mean lane four length.

1. confidence level: c = ______________
2. degrees of freedom: = ______________
3. t-critical: t_c = ______________
4. Error tolerance E: = ______________
5. Calculate the confidence interval for the population mean lane four length:
   
   P( ___________ ≤ µ ≤ ___________ ) = 0.95
6. _________ The international standard for the length of lane four is 424 meters. With a 95% level of certainty, does the confidence interval for lane four at the Pohnpei state track include this value?
7. _________ Does lane four of the Pohnpei state track conform to international standards?
8. _________ Will times run in lap four likely to too short or too long versus a track with lane four at the international standard length?

Confidence interval statistics
Find a tc value from a confidence level c and sample size n	tc		=TINV(1-c,n-1)
Calculate an error tolerance E of a mean for any n ≥ 5 using sx.	E		=tc*sx/SQRT(n)
Calculate a confidence interval for a population mean µ from a sample mean x and an error tolerance E		x-E≤ µ ≤x+E