(Q or the final exam in an engineering statistics course are known to be normall
ID: 3323882 • Letter: #
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(Q or the final exam in an engineering statistics course are known to be normally distributed with an average of 71 and a variance of 21, If a sample of 25 students taking the final exam in one year was selected at random #10) The marks with an average mark of 75, what is the portability that the standard deviation of this sample will exceed 6? (a) 1% (b) 2% (c) 2%-2.5% (d) 1%-2% (e) 2.5% Please answer all o tas questions and show work. Will rate 100% (Q #11 A viscometer located in Lab #1 is engaged to measure the viscosity of five liquid samples. The results are listed in the table below. In order to ascertain the measurement reliability, the same set of liquid samples is sent to another lab (Lab #2) for viscosity analysis. The collected data are also tabulated into the Table below. Construct the 95% confidence interval of the difference (Labl mims Lab 2) between the population mean viscosities measured in the two labs and determine whether the population mean viscosity measured in the two labs are different. Assume tha differences is normal. t the distribution of Viscosity (cP at 25 C) Sample #5 403 410 Sample #3 Sample #4 373 378 Sample #2 Lab #1 Lab #2 Sample #1 385 392 412 363 431 401 (a) (-30, 51); no (b) (-20, 44); no (c) (-11, 32); no (d) (5, 55); yes (e) (10, 64); yesExplanation / Answer
> lab1=c(385,412,431,373,403)
> lab2=c(392,363,401,378,410)
> t.test(lab1,lab2,paired=T)
Paired t-test
data: lab1 and lab2
t = 1.032, df = 4, p-value = 0.3604
alternative hypothesis: true difference in means is not equal to 0
95 percent confidence interval:
-20.28326 44.28326
sample estimates:
mean of the differences
12
Since p-value >0.05, we accept the null hypothesis of no difference between the two means and conclude that there is no significant difference in the means of the values obtained in two labs.
Thus, option (b).
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