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Data are provided on the samples of the number of chirps in one minute and temperature.

The significance level is 0.05.

The sample size (n) is 8.

Rank correlation coefficient is used to test the significance of the correlation between the two variables.

The null hypothesis is set up as follows:

There is no correlation between the number of chirps in one minute and temperature.

\({\rho _s} = 0\)

The alternative hypothesis is set up as follows:

There is a correlation between the number of chirps in one minute and temperature.

\({\rho _s} \ne 0\)

The test is two tailed.

Compute the ranks of each of the two samples.

For the first sample, assign rank 1 for the smallest observation, rank 2 to the next smallest observation, and so on until the largest observation.If some observations are equal, the mean of the ranks isassigned to each of the observations.

In a similar pattern, assign ranks to the second sample.

The following table shows the ranks of the two samples:

Since there are no ties present, the following formula is used to compute the rank correlation coefficient:

\({r_s} = 1 - \frac{{6\sum {{d^2}} }}{{n\left( {{n^2} - 1} \right)}}\)

The following table shows the differences between the ranks of the two values for every pair:

Here,

\(\begin{array}{c}\sum {{d^2}} = 1 + 1 + .... + 1\\ = 12\end{array}\)

Substituting the values in the formula, the value of\({r_s}\)is obtained as follows:

\(\begin{array}{c}{r_s} = 1 - \frac{{6\sum {{d^2}} }}{{n\left( {{n^2} - 1} \right)}}\\ = 1 - \frac{{6\left( {12} \right)}}{{8\left( {{8^2} - 1} \right)}}\\ = 0.857\end{array}\)

Therefore, the value of the Spearman rank correlation coefficient is equal to 0.857.

The critical values of the rank correlation coefficient for n=8 and\(\alpha = 0.05\)are -0.738 and 0.738.

Since the value of the rank correlation coefficient does not fall in the interval bounded by the critical values, the null hypothesis is rejected.

There is enough evidence to conclude that there is a correlation between the number of chirps in one minute and temperature.