When a securities firm acts as a(n) , it makes a market in specific securities by maintaining an inventory of those securities.

The average u.s. household has $178,600 in life insurance. the standard deviation is $25,500. a local insurance agent would like to see how households in his city compare to the national average, and selects a simple random sample of 30 households from the city. for the households in the city, the average amount of life insurance is $188,800. a. based on the sample results, construct a 95% confidence interval for the true average amount of life insurance for households in the city. b. test the h0 : $178,600 ? ? to determine if the city's sample average is significantly different from the u.s. average amount of life insurance per household. use the conventional levels of significance.