To check the average cost to repair a bridge, a random sample of n=55 bridges was chosen. The mean and standard deviation for the sample are $25,788 and $1,540, respectively. Records from previous years indicate an average bridge repair cost was $25,003: Use the sample data to test that the mean repair cost is greater than $25,003 at the level of significance 0.05. Let T_{obs} denote the observed value of the test statistics you use for testing the hypothesis.
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The Iowa Department of Transportation repaired hundreds of bridges in 1993. To check the average cost to repair a bridge, a random sample of n = 55 bridges was chosen. The mean and standard deviation for the sample are $25,788 and $1,540, respectively. Records from previous years indicate an average bridge repair cost of $25,003. Use the sample data to test that the 1993 mean μ is greater than $25,003. What is the test statistic T? (Please round to 2 decimals, e.g. 1.23)
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On studying the data, a manufacturer found out that the average difference between the estimate would you reach to test a hypothesis that there is no difference between the means of the estima t-Test: Paired Two Sample for Means Estimated Total Cost Actual Total Cost Mean 4500 4894 Variance 0 31915.55556 Observations 10 10 Hypothesized Mean Difference 0 df 9 t Stat -6.97 P(T<=t) one-tail 0.0000 t Critical one-tail 1.83 P(T<=t) two-tail 0.0001 t Critical two-tail 2.26
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