Question

Considering the following observations for an amount of polymerization of a certain specimen:

418 421 421 422 425 427 431 434 437 439 446 447 448 453 454 463 465

a) Using Minitab, construct and interpret a boxplot.

b) Is it plausible that the given sample observations were selected from a normal distribution?

c) Calculate a two-sided 95% confidence interval for true average amount of polymerization. Does the

interval suggest that 440 is a plausible value for true average? What about 450? (Use Minitab when

necessary)

Answer 1

Solution-

a) Boxplot is plotted in minitab.

Boxplot shows a blue box that is interquartile range for data.

In the box black line is Median of the data.

Boxplot also shows there is no outlies in the data.

b)

From the above probability plot we can say that it is plausible that the given sample observations are selected from a normal distribution.

c)

95% confidence interval for mean is calculated using minitab.

• the interval suggest that 440 is a plausible value for true average. Because 440 is lies between the interval.

• the interval is not suggest that 450 is a plausible value for true average. Because 450 is out of confidence interval.

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Thank you...!

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