statistics
posted by Maria E. S. on .
The Acme Company has developed a new battery. The engineer in charge claims that the new battery will operate continuously for at leas 7 minutes longer than the old battery. To test the claim, the company selects a simple random sample of 100 new batteries and 100 old batteries. The old batteries run continuously for 190 minutes with a standard deviation of 20 minutes; the new batteries, 200 minutes with a standard deviation of 40 minutes. Test the engineer's claim that the new batteries run at least 7 minutes longer than the old. Use a 0.05 level of significance. (assume that therre are no outliers in either sample.)

Use the appropriate statistical formula for this type of 2sample test. Calculate the test statistic using the information in the problem. Find your critical value using the appropriate table at .05 level of significance for a onetailed test. Compare your test statistic to the critical value from the table. If the test statistic exceeds the critical value from the table, reject the null. If the test statistic does not exceed the critical value, do not reject the null. Draw your conclusions from the results.