MS 150 Statistics Quiz 09 Fall 2004 9-10 • Name: _______________

Hypothesis Testing Using Confidence Intervals

Thirty-seven Japanese sumo rikishi (wrestlers) were measured for the holding force of their hands in the mid-1990s. The sumo wrestlers had a mean holding force of 170 pounds with a standard deviation of 24 pounds. The holding force values were normally distributed.

Construct a 95% confidence interval using a student's t-distribution for the population mean hand grip.

1. The confidence interval for the population mean holding force of their hands µ is:
   _________ < µ < _________
2. This year the elite top rikishi (sekiwake) have a population mean holding force of 185 pounds. Is this statistically significantly different from the mid-1990s value?

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