Question 984513: The wait times (in seconds) for fast food service at two burger companies were recorded for quality assurance. Using the data below, find the following for each sample.
Range
Standard deviation
Variance
Lastly, compare the two sets of results.
Company Wait times in seconds
Big Burger Company 105 67 78 120 175 115 120 59
The Cheesy Burger 133 124 200 79 101 147 118 125
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! Big B
Range is 59 to 175 or 116
SD is 34.96
Variance is 1222.29 (square sd)
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Cheesy
Range is 79 to 200 or 121
SD is 35.50
Variance is 1260.55
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Add the numbers; square the total, and divide by the number of items in data set.
Then square each number
Then add up the squares and divide by number of items in data set.
Subtract what you did first from what you did second.
Divide by ONE LESS than the number of items.
That is the variance.
Take the square root of the variance, and you have the sd.
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Compare them with a two sample t-test
Ho=mu1=mu2
Ha=not equal
alpha=0.05 P{reject ho|ho true}
test stat t with df 16
critical value: abs(t)> 2.12
Calculation is difference in means over sqrt { (s1^2/n1)+(s2^2/n2)}
Result t=-2.157. This is greater than the critical value (mean 1 is less), so that one concludes at the p=0.03 level that the means are not equal.
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