Monday, February 13, 2012

T Test. Need help with the statistics question below?

At the local burger Shop, the average wait for burgers and coke is 3.0 minutes with a 蟽 of .7 minutes. Recently a random sample of 25 customers found that their average wait was 2.75 minutes. At the 0.05 伪, 2 tail test determine if there is any statistical difference. Can the proprietor state that his average wait is less than 3 minutes?T Test. Need help with the statistics question below?
SINGLE SAMPLE TEST, "two-tailed test"

7 - Step Procedure for t Distributions



1. Parameter of interest: "渭" = population mean for average wait



2. Null hypothesis Ho: 渭 = 3.0



3. Alternative hypothesis Ha: 渭 鈮?3.0



4. Test statistic formula: t = (x-bar - 渭)/(蟽/SQRT(n))

x-bar = estimate of the Population Mean (statistical mean of the sample) [2.75]

n = number of individuals in the sample [25]

蟽 =standard deviation [0.7]

渭 = Population Mean [3.0]



5. Computation of Test statistic formula t = (x-bar - 渭)/[s/SQRT(n)]

t = (2.75 - 3.0)/[0.7/SQRT(25)] = -0.7986

[0.7986 by symmetry of t-distribution]



6. Determination of the P-value: test based on n -1 = 24 df (degrees of freedom). Table "look-up"

value shows P-value "area under 24 df curve" to right of t = 0.216



7. Conclusion: For 95% confidence interval (significance value 伪 = 0.05/2 "two-tailed"), above

shows P-value %26gt; 伪, [0.216 %26gt; 0.05/2] so cannot reject Null hypothesis Ho: 渭 = 3.0.



No; proprietor cannot claim to a 95% confidence level the wait is less than 3 minutes.

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