Final answer:
The manager can conclude that the employee time required to process high-efficiency lamp bulb rebates is lower than 3.6 minutes.
Step-by-step explanation:
To test the manager's claim, we will conduct a one-sample t-test. The null hypothesis (H0) is that the mean time required to process high-efficiency lamp bulb rebates is not lower than 3.6 minutes. The alternative hypothesis (Ha) is that the mean time is lower than 3.6 minutes.
To calculate the test statistic, we will use the formula: t = (x - μ) / (s / sqrt(n)), where x is the sample mean, μ is the population mean (3.6), s is the sample standard deviation, and n is the sample size. Plugging in the values, we get t = (3.4 - 3.6) / (1.2 / sqrt(50)) = -2.07.
The p-value can be calculated using the t-distribution table or software. At a significance level of 5%, the critical value for a one-tailed test is -1.677. Since the test statistic (-2.07) is less than the critical value, we can reject the null hypothesis. Therefore, we have enough evidence to conclude that the employee time required to process high-efficiency lamp bulb rebates is in fact lower than 3.6 minutes.