Formula for calculating work sampling? - Answers

Calculating the Sample Size The sample size, in this case, refers to the number of children to be included in the survey. Step 1: Base Sample-size Calculation The appropriate sample size for a population-based survey is determined largely by three factors: (i) the estimated prevalence of the variable of interest - chronic malnutrition in this instance, (ii) the desired level of confidence and (iii) the acceptable margin of error. For a survey design based on a simple random sample, the sample size required can be calculated according to the following formula. Formula:n= t² x p(1-p)m²Description: n = required sample sizet = confidence level at 95% (standard value of 1.96)p = estimated prevalence of malnutrition in the project aream = margin of error at 5% (standard value of 0.05) Example In the Al Haouz project in Morocco, it has been estimated that roughly 30% (0.3) of the children in the project area suffer from chronic malnutrition. This figure has been taken from national statistics on malnutrition in rural areas. Use of the standard values listed above provides the following calculation. Calculation: n= 1.96² x .3(1-.3).05²n = 3.8416 x .21.0025n = .8068 .0025 n = 322.72 ~ 323Calculating the Sample Size The sample size, in this case, refers to the number of children to be included in the survey. Step 1: Base Sample-size Calculation The appropriate sample size for a population-based survey is determined largely by three factors: (i) the estimated prevalence of the variable of interest - chronic malnutrition in this instance, (ii) the desired level of confidence and (iii) the acceptable margin of error. For a survey design based on a simple random sample, the sample size required can be calculated according to the following formula. Formula:n= t² x p(1-p)m²Description: n = required sample sizet = confidence level at 95% (standard value of 1.96)p = estimated prevalence of malnutrition in the project aream = margin of error at 5% (standard value of 0.05) Example In the Al Haouz project in Morocco, it has been estimated that roughly 30% (0.3) of the children in the project area suffer from chronic malnutrition. This figure has been taken from national statistics on malnutrition in rural areas. Use of the standard values listed above provides the following calculation. Calculation: n= 1.96² x .3(1-.3).05²n = 3.8416 x .21.0025n = .8068 .0025 n = 322.72 ~ 323