1. A light bulb manufacturer claims their light bulbs last for 1,000 hours.

You sample 50 light bulbs and you find that the sample average light bulb lifetime duration is 955 hours. Assume that you know the population standard deviation, and that it is 220 hours. That is , ,.

Test the null hypothesis against the alternative hypothesis at the 0.05 significance level.

1. Calculate the critical statistic using the qnorm() function. Compare this to the test statistic, found using the sample information. Do you reject, or fail to reject the null hypothesis?
2. Find the p-value associated with the sample statistic under the null hypothesis. You can do this using the pnorm function. Report the p-value. Is your conclusion consistent with part (a)?