Hi! I am having trouble understanding how to construct confidence intervals for these problems. Your help is greatly appreciated.

Read the following scenario and complete each of the problems below: A flashlight company claims that the new bulb in its heavy duty flashlight will average 246 hours of light. A statistics student decides that helshe wants to test this claim at a 5% level of significance to determine if there is evidence to support the claim. The student randomly selects and tests 15 flashlight bulbs and records how long the bulb lasts until it burns out. Assume the life of a bulb is normally distributed. The data is in the table below: Tm 1 2 3 10 11 12 13 14 15 HE: 246 224 231 242 237 240 243 236 239 255 256 239 247 231 253 A. The standard deviation of the mlation is 7.4 hours. Construct a 95% confidence interval for this study. B. Same scenario. but the population's standard deviation is not known. Construct a 95% confidence interval for this study. A. The standard deviation of the mfaon is 7.4 hours. Construct a 95% confidence interval for this study. B. Same scenario, but the population's standard deviation is not known. Construct a 95% confidence interval for this study. 0. Write a statement comparing and contrasting the two confidence intervals and results