# Solve: Type I and Type II Errors

Dr. Easy saw the scores from the MA-222 test and used the occasion to test the old adage that girls are smarter than boys on subjects tested by ACT. Assume the degrees of freedom for this problem is 28. Dr. Easy did the arithmetic and found the value of the test statistic was 2.69 (alpha equals .05). What is the critical value (3 decimal places of significance)? If the mean of the boys score was lower than the mean of the girls score can she reject her null hypothesis? Yes or No.

Students at the University of Arkansas randomly selected 217 student cars and found that they had ages with a mean of 7.89 years and a standard deviation of 3.67 years. They also randomly selected 152 faculty cars and found that they had ages with a mean of 5.99 years and a standard deviation of 3.65 years. Use a 0.01 significance level to test the claim that student cars are older than faculty cars. What are the critical value (3 places of significance) and t score (2 places of significance)? Are student cars older (Yes or No)?

Customer waiting times are studied at the Jefferson Valley Bank. When 25 randomly selected customers enter any one of several waiting lines, their times have a mean of 6.896 minutes and a standard deviation of 3.619 minutes. When 20 randomly selected customers enter a single main waiting line that feeds the individual teller stations, their waiting times have a mean of 7.460 minutes and a standard deviation of 1.841 minutes. Use a 0.05 significance level to test the claim that waiting times for the single line have a lower standard deviation. What are the critical value and F test value, each to 3 decimal places of precision? Do you reject the null hypothesis (Yes or No)?

Customer waiting times are studied at the Jefferson Valley Bank. When 25 randomly selected customers enter any one of several waiting lines, their times have a mean of 6.896 minutes and a standard deviation of 3.619 minutes. When 20 randomly selected customers enter a single main waiting line that feeds the individual teller stations, their waiting times have a mean of 7.460 minutes and a standard deviation of 1.841 minutes. Use a 0.05 significance level to test the claim that waiting times for the single line have a lower standard deviation. What are the critical value and F test value, each to 3 decimal places of precision? Do you reject the null hypothesis (Yes or No)?

#### Solution Summary

Step by step method for testing the hypothesis under 5 step approach is discussed here. Excel template for each problem is also included. This template can be used to obtain the answers of similar problems.