Question 6. 18 pts In one of the studies, it was found that, in a random sample of 261 married persons, 135 were smokers while in a sample of 239 non-married persons there were 131 smokers. (a)- (5pts) Find a 90% confidence interval for the true difference in proportion of smokers among the married and non-married populations. (b)- (2pts) Interpret this confidence interval. (c)- (3pts) Based on the above interval, can one conclude that there is a significant difference between the proportions of smokers in the two populations ? Justify your answer. 5 (d)- (8pts) Do a formal hypothesis testing to test whether the two populations' propor- tions are significantly different. Use a = 0.10. Is the conclusion same as the one in part (c)