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help please I have exam today ....show steps Suppose that data set A is {1, 3, 5

ID: 3205580 • Letter: H

Question

help please I have exam today ....show steps

Suppose that data set A is {1, 3, 5, 6, 10}, data set B is {2, 15, 17, 25, 35}, and the standard or true value is 18. Which data set is more precise? A because it has a smaller amount of spread. B because its sample average is closer to the true value of 18. B because it has larger values on average. Both, because the sample sizes are the same. Suppose that fiber strength is normally distributed with mean mu=75 N/m^2 and standard deviation sigma=2.5 N/m^2. According to the 68-95-99.7 Rule, what percent of fibers is weaker than 70 N/m^2? 2.5% 5% 95% 97.5%

Explanation / Answer

7. Precision refers to how closely the samples from data set are related to the standard or true value. Therefore, comparing two data sets, range of set A is:

Range: Maximum-Minimum

=10-1=9

and range of set B is 31.

Therefore, set A is more precise, because it has lower range compared to set A.

Ans: A.

8. Substitute the given values in following formula to compute the Z score.

Z=(X-mu)/sigma, where, X is the raw score, mu is the population mean fibre strength, and sigma is population standard deviation of fibre strength. Next, look into standard normal table to find area corresponding to Z score. The table gives area under standard normal curve to the left of Z. Multiply the probability with 100 to compute the required probability.

P(X<70)=P[Z<(70-75)/2.5]=P(Z<-2)=0.0228

Thus, around 2.28% of fibres are weaker tahn 70N/m^2.

Ans: A