Question

A certain enzyme in the liver of fish is considered an indicator of trace amounts of a dangerous pollutant that is difficult to detect by chemical methods. Enzyme activities of less than 50 units per gram of liver (fresh weight) are taken to indicate the presence of the pollutant. A random sample was taken from a local stream and the enzyme concentrations were as follows. 48 43 51 42 50 42 44 45 56 49 44 47 50 49 38 46 38 52 32 56 Compute a 95% and 99% confident interval for the mean enzyme activity for the fish population in this stream. (You will have to include the conf.level- 0.99 in the R code for the t.test. 2. Do a hypothesis test on this data. 3. Are enzyme activities depressed in this population?

Answer 1

Mean e inte

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studio ble Sode ew lots ession uild eua rotle Lools Help Project: (None) - Environment History Connections Source on Save List ▼ X-ba r = sample mean , s= sample sd, n=sample sıze , #ст = cont1 dence 1nterval, Global Environment 2 #1 c1 =lower confidence limit, uc1=upper confidence limit 3 ci <-c(0.95,0.99) 4 x <c(48,43,51,42,50,42,44,45,56,49,44,47,50,49,38,46, 38,52,32,56) 5 n <- length(x) 6 x_bar <- mean(x) 7 s <-sqrt ((sum (XA2)-n® (X-bar.. 2) )/ (n-1)) values ci 1cl num [1:2] 0.95 0.99 num [1:2] 43.3 42.2 20L 6.02538489707462 num [1:2] 2.09 2.86 num C1:2] 48.9 50 num [1:20] 48 43 51 42 50 42 4. 46.1 <-abs (qt (0.5-(1-ci),n-1,lower.tail = TRUE)) 9 (t s)/(sqrt (n)) 11 ucl <- x bar+(t s)/(sqrt (n)) 13 print (ucl) uc 10 lcl <- x_bar-(t s)/(sqrt (n)) 12 print (lcl) 14 x bar Flles Plots Packages Help Vlewer qt 14:1 (lop Level) R Script R: The Student t DistributionFind in Topic Console Terminal ncp > print(lcl) [1] 43.28003 42.24541 > print(ucl) [1] 48.91997 49.95459 2 TRUE, TRUE, log.p log . p FALSE) FAT,SR) = = OType here to scarch a e ik 4: AM 16-Jan-19