Question

You want to rent an unfurnished one-bedroom apartment for next semester. You take a random sample of 10 apartments advertised in the local newspaper and record the rental rates. Here are the rents (in dollars per month).

645, 340, 515, 455, 530, 655, 320, 465, 435, 615

Find a 95% confidence interval for the mean monthly rent for unfurnished one-bedroom apartments available for rent in this community.

Answer 1

First let us find sample mean

Create the following table.

data	data-mean	(data - mean)2
645	147.5	21756.25
340	-157.5	24806.25
515	17.5	306.25
455	-42.5	1806.25
530	32.5	1056.25
655	157.5	24806.25
320	-177.5	31506.25
465	-32.5	1056.25
435	-62.5	3906.25
615	117.5	13806.25

Find the sum of numbers in the last column to get.

So standard deviation is

Let us assume distribution is normal

t value is TINV(0.05,9)=2.262

So Margin of Error is

Hence CI is