00:01
Hello students, in the question, they given that annual starting salaries for college graduates with degrees in business administrations are generally expected to be between $30 ,000 and $35 ,000.
00:20
Then the given confidence interval as 95 % is equal to 1 -0 .95, we get 0 .05.
00:30
Then for the subpart a, we need to find the population standard deviation.
00:37
The population standard deviation which is denoted as sigma that is 35 ,000 -30 ,000 divided by 4, we get 5 ,000 by 4.
00:56
The standard deviation is equal to $1 ,250.
01:00
Then for the subpart b, we need to find how large a sample should be taken if the desired margin of error which is denoted as e that is 500.
01:20
Then the formula of calculating the margin of error e is equal to z into sigma by square root of n.
01:34
Here the z alpha by 2 which is equal to z 0 .05 by 2, we get 1 .96...