204 exm4 sp10 key0 - Math 2040 exam 4 spring 2010 Name_...

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Math 2040 exam 4 spring 2010 Name______________________________ SHOW YOUR WORK TO RECEIVE CREDIT 1 ) A statistical test was performed as follows: Ho: μ = 42 sample mean 40.4 σ = 4.8 n =16 Ha: μ < 42 Assuming the sample means are normally distributed: a) What is the p-value of the above test? normalcdf(0,40.4,42,4.8/ 16) __.0912__ b) Interpret what this value means with respect to the above Ho. For the above test, if μ = 42 then P( 40.4) = .0912 2) A large city on the Atlantic coast sends treated sewage out to the ocean by means of pipe extending ½ mile into the ocean. A marine ecological researcher studied the effect of the sewage on the sea-floor biomass of organisms for 8 different types ocean bottom near the pipe Sea-floor biomass (kg/m 2 ) Ocean bottom type 1 2 3 4 5 6 7 8 50 meters from pipe outflow 2.4 2.1 1.9 2.0 1.5 1.1 0.9 0.5 300 meters from pipe outflow 2.2 2.1 1.5 1.8 1.2 0.8 1.0 .4 50m biomass – 300m biomass .2 0 .4 .2 .3 .3 -.1 .1 in List 1 Is this sufficient evidence at the 5% significance level that the biomass is larger at 50 meters from the pipe outflow compared to 300 meters? T test t = 2.96 Ho: d = 0 0 = 0 p = .010 Ha: d > 0 list L1 α > 0 yes paval = .010 < .05 3) A group of archeologists want to test if the proportion of amphora jars having a polychrome style is less at a particular site level than the 20% at lower levels so they take sample of 32 amphora at that level and find 4 are of polychrome style. Test the hypotheses Ho: p = .20 against Ha: p < .
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204 exm4 sp10 key0 - Math 2040 exam 4 spring 2010 Name_...

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