University:
Skagit Valley College
Course:
MATH 146 | Introduction to Stats
Academic year:

2023
Views:

60

Pages:

8
Author:

M. Hamilton

Introduction dependant 10.4 1) Mean entry-level salaries for college graduates with mechanical engineering degrees and electrical engineering degrees are believed to be approximately the same. A recruiting office thinks that the mean mechanical engineering salary is actually lower than the mean electrical engineering salary. The recruiting.office.randomly surveys.50.entry level.mechanical.engineers and 60.entry. level electrical engineers. The sample of mechanical engineers had a mean salary of $46,100 and a standard deviation of $3,450. The sample of electrical engineers had a mean salary of $46,700 and a standard deviation of $4,210. Deción Are the salaries of mechanical engineers-lower, on average, than mechanical engineers? 2) A pharmaceutical company is interested in producing echinacea supplements. However, before going into production, they want to test the effectiveness of echinacea in reducing rhinovirus infections (viruses that typically cause common colds). wo Gow iad of In a test of the effectiveness of echinacea, 40 of the 50: subjects treated with echinacea developed thinovirus infections. In a placebo group, 88 out of the 103 subjects developed rhinovirus infections. one now. Question 4o beans How could the pharmaceutical company determine if their supplement is effective in reducing rhinovirus infections? 10.4 3) A new fuel treatment was designed to increase fuel efficiency in vehicles. The fuel efficiency of the vehicles was measured before and after the fuel treatment was applied. Six vehicles were randomly selected and the data are shown in the table below. The differences have a normal distribution. Ore Vechide dater Vehicle Before A 22.5 31.2 25.1 19.8 27.6 What is the differenee? mary points. After 24,1 B 35.8 C 27.2 D 20.1 E 35.4 Do the data suggest that the fuel treatment is effective in increasing a vehicle's fuel efficiency? What are matched.or.paired samples? Samples are dependent /dependent on each together Ex: Scumple depends on the Same thing Measurements (data) are obtained from either-a-single-individual (or-object)-or-from- individuals that are somehow "connected." Examples Pre Post test scores/Befac & After (Ithing makes tor 1. Siblings Heights two things connected some whol Blood Preasure measurments in each arm Requirements when working with matched or paired samples: 1)-Simple-andom sampling is used 2) Sample sizes are small surments: 3) Two measurements (samples) are drawn from the same individual (or ojbect) or a pair of individuals (or objects). sample 4) Differences are calculated from the matched or paired samples. 5) The differences form the sample that is used for the hypothesis test. (9.5) Measurment difference assume theer 6) Either the matched or paired samples have differences that come from a population that is normal or the number of differences is sufficiently large so that the distribution of the sample mean of differences is approximately normal hormal 1730 Notation for differences: frean Mean of the differences = differences Standard deviation of the differences d s. Adifference