A company advertised phone batteries with a mean standby time of 235 hours. A phone shop manager feels that the batteries have a standby time of less than 235 hours. The manager conducts an experiment and collects the following summary statistics:
n=100∑x=23250∑x2=5468125 n = 100 \quad \sum x = 23250 \quad \sum x^2 = 5468125 n=100∑x=23250∑x2=5468125Find the mean and standard deviation of the sample.
Carry out a hypothesis test to test the manager's claim at the 1% significance level. State your assumptions clearly.
616 exam-style questions on Edexcel A Level Maths The Normal Distribution, covering 3.1 The Normal Distribution, 3.2 Finding Probabilities for Normal Distributions, 3.3 The Inverse Normal Distribution Function, 3.4 The Standard Normal Distribution, 3.5 Finding the mean and standard deviation, 3.6 Approximating a Binomial Distribution, and 3.7 Hypothesis Testing with the Normal Distribution. Each one has a worked solution and a mark scheme showing where the marks go.