help please

Researchers randomly studied the relationship, if any, between male and female grade point averages in a population of seniors who were not intending to go to college after high school. They wanted to construct a 95% confidence interval for this study on 50 men and 50 women. The mean average gpa for the men was 2.9 with a standard deviation of 0.5 and the mean average gpa for the women was 3.1 with a standard deviation of 0.4. Construct the confidence interval for the difference of two sample means. O (2.9, 3.1) O (-2.0, 0.05) (0.026, 0.374) O (-0.396, -0.004) (2.80, 2.99)1. The lifetime for a certain brand of widgets is normally distributed. A random sample of 25 widgets is taken and a sample mean lifetime of 520 hours with a standard deviation of 50 hours. Before taking the sample, researchers speculated that the mean lifetime of the widgets is no more than 500 hours. Answer the questions below using the given information. a) null hypothesis: Ho : H= 520 b) the alternative hypothesis: HA : |