Week 4 Assignment Template: Minivan MPG Report
Prepared by: Lisa Ayers
Date: 11/05/2023
Walden University
Introduction
I have been tasked with conducting an independent test on a car manufacturer's claim regarding
the highway gas mileage of their latest model minivan. The manufacturer claims that their
minivans get 28 miles per gallon on the highway. To validate this claim, we selected a random
sample of 35 low-mileage fleet minivans and recorded their highway mileage.
Our objective is to calculate the sample mean and standard deviation of the data and then create a
95% confidence interval to assess whether the company's claimed mean of 28 miles per gallon
falls within this interval. The confidence interval will provide us with a range of values within
which we are reasonably confident that the true mean lies.
Part 1: Sample Mean, Standard Deviation, and Confidence Interval
Calculating the Confidence Interval - start by calculating the sample mean and standard
deviation of the data. The sample mean (x
) represents the average mileage in our sample,
and the standard deviation (s) measures the spread or variability of the data.
Sample Mean (x
) = (29.7 + 24.5 + ... + 26.1) / 35 Sample Standard Deviation (s) = √[(Σ(xi -
x
