A random sample of 10 motorists buying petrol are found to spend an average of £58.30 with estimated standard error £5.25. Calculate a 95% confidence interval for the expected spending of motorists at this petrol station.

Ignacio Riggs

Ignacio Riggs

Answered question

2022-10-22

A random sample of 10 motorists buying petrol are found to spend an average of £58.30 with estimated standard error £5.25. Calculate a 95% confidence interval for the expected spending of motorists at this petrol station.
I got 10 of these questions so if someone can help me do this one i think i can do the rest.

Answer & Explanation

Amadek6

Amadek6

Beginner2022-10-23Added 21 answers

Step 1
Your interval is defined by
( x ¯ z σ N ,   x ¯ + z σ N )
Step 2
You already know x ¯ = 58.3 ,   N = 10 ,   σ = 5.25. Your z∗ value is determined by how wide you want your confidence interval. Since you want a 95% interval and know that 95% of a normally distributed population is contained within 1.96 standard deviations from the mean, you want z = 1.96. The rest is just a matter of plugging in numbers. Your sample size is extremely small, so you may also want to make a note of that in your answer.

Do you have a similar question?

Recalculate according to your conditions!

New Questions in College Statistics

Ask your question.
Get an expert answer.

Let our experts help you. Answer in as fast as 15 minutes.

Didn't find what you were looking for?