# Maths

Read the sections on Hypothesis Testing in your book. Click on these links … http://college.cengage.com/mathematics/blackboard/shared/content/video_explanations/video_wrapper.html?filename=v01090a http://college.cengage.com/mathematics/blackboard/shared/content/video_explanations/video_wrapper.html?filename=v01090b http://college.cengage.com/mathematics/blackboard/shared/content/video_explanations/video_wrapper.html?filename=v02262a Note that there are also other helpful links/videos listed in the Forum discussion. Think of an application where you can use hypothesis testing to test a premises. Use .05 for your alpha and give the scenario. Set up the problem, solve it and state your conclusions. See the example below. Then respond to at least 2 classmates. First post: 1. First summarize the 3 videos and make a note of what you learned. 2. Then, create your own hypothesis test for your classmates. You MUST provide the correct answer for your problem — a key, so that classmates will know whether or not their answers to you are correct. Example: XYZ car company boasts that its new car Eco Auto gets at least 59 miles to the gallon. Given a sample mean of 57 and a standard deviation of 3.5 where 35 people were tested, find the z value and p score. Hint: Use the P value calculator in the announcements to find the p score. Note: On this one you do not need to attach an excel spreadsheet. Example student response that explains all work in detail Ha: u=59 gives the solutions: and In the formulas below it is not explained that the first is the z test formula, which is Z = (xbar – m) /(s / sqrt(n)) = 57 xbar = sample mean Where m= 59 = hypothesized population mean s= 3.5 = population standard deviation = 35 n = sample size In the examples below the xbar and m values are switched = (57-59)/ (3.5/35^.5) = -3.38 You can put this in excel or your calculator. This is entered into an Excel cell like you would a calculator. =norm.dist(57,59,3.5/35^.5,true) or enter this in excel NORM.DIST(x,mean,standard_div,cumulative) To enter the information into Excel, Where: x = xbar, mean = the sized population mean, standard_dev = population standard deviation, cumulative = /srqrt(n) or n^0.5, and add ,true for the condition test. and hit enter =norm.s.inv(A) and type this in excel Then take that value which we will call A This takes a two-step process in Excel to get to a final z value using the NORM.DIST and NORM.S.INV functions. and hit enter p=.000362 Using the z to p value calculator with a=.05, 1 tailed test and z=-3.38, you get Since p < .05, you reject the null