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LSD and Tukey yardsticks on five treatments. Also two-way Anova test on same set of data.

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Complete the ANOVA table corresponding to this data, entering values to 2 decimal places.

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
SourcedfSSMSVR
Between Treatments$\\var{m-1}$$\\var{btss}$$\\var{msbt}$[[3]]
Between Blocks[[0]][[2]]$\\var{msbb}$$\\var{vrbb}$
Residual$\\var{dfr}$$\\var{rss}$$\\var{rs}$-
Total[[1]]$\\var{tss}$--
\n

$\\sqrt{RMS}=\\var{sqrms}$ to 2 decimal places. This will be used later to calculate the yardsticks.

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Given the value of $VR$ in the table above, find the range for the $p$ value by using the critical values of $F_{3,12}$ (one-sided) below.

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
$10\\%$$5\\%$$1\\%$$0.1\\%$
$2.61$$3.49$$5.95$$10.8$
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$p$ less than $0.1\\%$

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$p$ lies between $0.1\\%$ and $1\\%$

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$p$ lies between $1 \\%$ and $5\\%$

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$p$ lies between $5 \\%$ and $10\\%$

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$p$ is greater than $10\\%$

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Given the $p$-value and the range you have found, what is the strength of evidence against the null hypothesis that there is no difference in the treatments offered by the creams?

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Hence what is your decision based on the above ANOVA analysis?

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Using the yardsticks

\n

The sample means for the creams are

\n

W: {me[0]}, X: {me[1]}, Y: {me[2]}, Z: {me[3]}

\n

Using $q_{t,\\nu}(\\alpha) =4.2$, $t_{\\nu}(\\alpha) =2.179$ and the value for $\\sqrt{RMS}$ above, calculate the LSD and Tukey yardstick.

\n

LSD yardstick value =    [[0]] (to 2 decimal places). 

\n

Tukey yardstick value = [[1]] (to 2 decimal places).

\n

 

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Using these yardsticks fill in the following table indicating if there is a possible or definite significant difference between the sample means of pairs of creams.

\n

 

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To test the effectiveness of pain-relief creams on back pain, five volunteers (A-E) suffering with back pain tried each of four creams (W-Z). The degree of pain relief was measured on a 0-50 scale (higher figures indicate higher levels of pain relief). The results are given below with some totals:

\n

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
 ABCDETotals
W{r[0][0]}{r[1][0]}{r[2][0]}{r[3][0]}{r[4][0]}{cols[0]}
X{r[0][1]}{r[1][1]}{r[2][1]}{r[3][1]}{r[4][1]}{cols[1]}
Y{r[0][2]}{r[1][2]}{r[2][2]}{r[3][2]}{r[4][2]}{cols[2]}
Z{r[0][3]}{r[1][3]}{r[2][3]}{r[3][3]}{r[4][3]}{cols[3]}
Totals{t[0]}{t[1]}{t[2]}{t[3]}{t[4]}{tot}
\n

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 Using the Yardsticks

\n

The mean values for each cream are:

\n

  

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
 $\\overline{x}_i$
W$\\var{me[0]}$
X$\\var{me[1]}$
Y$\\var{me[2]}$
Z$\\var{me[3]}$
\n

The differences between the mean values for the creams are:

\n

Between $W$ and $X=\\;|\\var{me[0]}-\\var{me[1]}|=\\var{abs(me[0]-me[1])}$

\n

Between $W$ and $Y=\\;|\\var{me[0]}-\\var{me[2]}|=\\var{abs(me[0]-me[2])}$

\n

Between $W$ and $Z=\\;|\\var{me[0]}-\\var{me[3]}|=\\var{abs(me[0]-me[3])}$

\n

Between $X$ and $Y=\\;|\\var{me[1]}-\\var{me[2]}|=\\var{abs(me[1]-me[2])}$

\n

Between $X$ and $Z=\\;|\\var{me[1]}-\\var{me[3]}|=\\var{abs(me[1]-me[3])}$

\n

Between $Y$ and $Z=\\;|\\var{me[2]}-\\var{me[3]}|=\\var{abs(me[2]-me[3])}$

\n

We compare these differences with the LSD and Tukey yardsticks:

\n

LSD yardstick = $2.179\\times\\var{sqrms}\\times\\sqrt{2/\\var{n}}=\\var{lsd}$ to 2 decimal places, where $\\var{sqrms}$ is the value of $\\sqrt{RMS}$ found above.

\n

Tukey yardstick = $4.2\\times\\var{sqrms}\\times\\sqrt{1/\\var{n}}=\\var{tukey}$ to 2 decimal places.

\n

If the difference of the means:

\n\n

 

\n\n

 

\n\n

 

\n

Hence we have the following for the creams:

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Pairs of creamsDefinite Significant DifferencePossible Significant DifferenceNo Significant Difference
Means of W and X{yn[0][0]}{yn[0][1]}{yn[0][2]}
Means of W and Y{yn[1][0]}{yn[1][1]}{yn[1][2]}
Means of W and Z{yn[2][0]}{yn[2][1]}{yn[2][2]}
Means of X and Y{yn[3][0]}{yn[3][1]}{yn[3][2]}
Means of X and Z{yn[4][0]}{yn[4][1]}{yn[4][2]}
Means of Y and Z{yn[5][0]}{yn[5][1]}{yn[5][2]}
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