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1. Use the following minitab commands (Click \"Editor\" then \"Show Command Line

ID: 3050289 • Letter: 1

Question

1. Use the following minitab commands (Click "Editor" then "Show Command Line" to ac- tive command line editor) to generate 8 observations: MTB set cll DATA> 56 288127 DATA> end MTB > random 8 c12; SUBC normal 0 0.7. MTB > let c1=c11+c12 a. [3 Use Minitab to compute the standard deviation of the numbers in cl (type 'describe cl' to see summarv measures). The answer is b. [3] Add 2.5 to each number ('Let c2=c1+2.5, will do this, assuming the raw data are in c1). Now compute the standard deviation: with that in part (a)? . How does your answer compare c. 3 Multiply the data in (a) by 4 and compute the standard deviation (Let c3-c1*4) How does your answer compare with that in part (a)? (If you are not sure, divide the standard deviation of part (c) by the one of part (a).)

Explanation / Answer

MTB > random 8 c12

MTB > let c1=c11+c12

MTB > describe c1

Descriptive Statistics: C1

Variable N N* Mean SE Mean StDev Minimum Q1 Median Q3 Maximum
C1 8 0 4.879 0.893 2.527 2.053 2.207 5.191 7.150 8.444

MTB > let c2=c1+2.5
MTB > describe c2

Descriptive Statistics: C2

Variable N N* Mean SE Mean StDev Minimum Q1 Median Q3 Maximum
C2 8 0 7.379 0.893 2.527 4.553 4.707 7.691 9.650 10.944

MTB > let c3=c1*4
MTB > describe c3

Descriptive Statistics: C3

Variable N N* Mean SE Mean StDev Minimum Q1 Median Q3 Maximum
C3 8 0 19.52 3.57 10.11 8.21 8.83 20.76 28.60 33.78

____________________________________________________________________________________________

a)

Standard deviation of number in C1 is  2.527

b)

Standard deviation of number in C2 is  2.527

Comparision - Standard deviation of number in C1 is equal to Standard deviation of number in C2 because due to adding 2.5 (constant) in C1 there is no any change in standard deviation and there is small shift in the mean.

c)

Standard deviation of number in C3 is   10.11

Due to multiplication of C1 by 4 the mean shifted to 1952 which results increase in the standard deviation.

10.11 / 2.527 = 4.001