imagine you re in a queue to the airport check-in desk if two-thirds of the queue

Step-by-step explanation:

Let x be the number of people in the queue, including yourself.

We have 2/3 x + 1 + 3/10 x = x.

=> 29/30 x + 1 = x

=> x/30 = 1

=> x = 30.

Hence there are 30 people in the queue.

[a]. sample is 25 randomly selected students

    also population is all students

[b]. (20.0, 23.0)

[c]. (8.8, 24.2)

Step-by-step explanation:

here is a step by step process to solving this, i hope you find this helpful.

1). The population is all students who graduated from his school  while the

sample is 25 randomly selected students from the email list

2). given alpha = 1-0.86=0.14

critical z value(two tailed) for 86% confidence level is:

z=normsinv(0.07) or normsinv(0.93)=1.476

Margin of error=1.476*(4.6/SQRT(20))=1.5

86% confidence interval for population mean

=21.5+/-1.5

=(20.0, 23.0)

3). if population standard deviation is not known,we will use t distribution.

df=20-1=19

t*=tinv(0.05,19)=2.093

Margin of error=2.093*(5.7/sqrt(20))=2.7

95% confidence interval for population mean

=21.5+/-2.7

=(18.8, 24.2)

cheers i hope this helps