SMS 3213 MMSUT Standard Deviation & Interactive Statistics Questions

SMS 3213: INTRODUCTION TO COMPUTER INTERACTIVE STATISTICS
DATE: 2/11/2023
DEADLINE: 15/11/2023
ASSIGNMENT 1
a) A population is normally distributed with a mean 7 and standard deviation 2. How big
should the sample be if at 95% confidence interval the size of  is 0.03?
(5 marks)
b) A trucking firm suspects the claim that the average lifetime of certain tyres is at least 28,000
miles. To check the claim, the firm puts 40 of these tyres on its trucks and gets them mean
lifetime of 27463 miles with standard deviation of 1,343 miles. What is the conclusion of the
firm if the probability of type 1 error is to be at most 0.01?
(5 marks)