**3.2 Methods of data analysis**

### *3.2.1 Climate data analysis*

Climate data was analyzed based on time series analysis. It carries insightful importance in business and policy planning. It's applicable for a number of purposes including to study the past behavior of the phenomena under consideration; to compare the current trends with that in the past or the expected trends and to compare the performance of two different series of a different type for the same time duration. Mann–KENDALL TEST AND SEN'S SLOPE ESTIMATES (MAKESENS) was employed to test the trends the rainfall and temperature of the study area over last 31 years—1987–2017. Unlike a parametric analysis, in a regardless of the normal distribution of the population (*N*) of the study, the nonparametric regression (Mann–Kendall's (MK) test) fits for temporal scale changes of the units corresponding to each times. Thus, it was employed to test the rainfall and temperature trends of all 31 years (372 months) of Western Sidama drought prone districts.

The Mann–Kendall (MK) trend test tool [25–27] is commonly used, from among other alternative models of trend analysis, to determine if a trend exists, and can handle seasonal patterns within the data.

For the time series *x*1, … , *xn*, the MK test uses the following statistic equation:

$$\mathbf{S} = \sum\_{i=1}^{n-1} \sum\_{j=k+1}^{n} \mathbf{Sign}(\mathbf{Xj} - \mathbf{Xi}) \tag{2}$$

If *S* > 0, then later observations in the time series tend to be larger than those that appear earlier in the time series and *s* = 0 implies no difference while the reverse is true if *S* < 0.

#### **3.3 Standardized precipitation index (SPI)**

The standardized precipitation index (SPI) is a widely used index to characterize meteorological drought on a range of timescales.

$$\text{SPI} = \text{X-Xm/SD} \tag{3}$$

Where,

*X* is actual precipitation; Xm, mean precipitation; SD, standard deviation. Weather conditions per SPI value (**Table 2**).

#### *3.3.1 Survey data analysis*

Survey data was analyzed by using descriptive statistics.

#### *3.3.2 PRA data analysis*

Data from this source was analyzed based on issue by issue and case by case augmentation in such a way to ensure triangulation.

*Climate Change in Ethiopia: Implication on Human Capital in Rural Community - Case Study… DOI: http://dx.doi.org/10.5772/intechopen.98993*


#### **Table 2.**

*Standardized precipitation index.*
