I'm doing research in veterinary science and topic is associated with ticks prevalence and seasonal variation in cow..I have randomly selected 560 cows as sample size and studing for prevalence and seasonal variation in a longitudinal studies.. please tell me is 560 a good sample size for statistical calculation such as p-value, correlation, chi-square and Anova? Please help me
Hi,
This depend of:
· The expected prevalence: check for the sample size formula and considering you expected prevalence, confidence interval and the confidence level you can find out if your sample size is robust or not
n=(Z^2.p.(1-p))/E^2
with:
Z is the Z-score for the desired confidence level (e.g., 1.96 for 95% of confidence)
p is the expected prevalence
E is the desired margin error
· Geographical Variability: If tick prevalence varies significantly across different regions of your country, ensure your sample includes cows from various regions to account for this variability
And don’t forget, to adjust for the design effect (DE)
@tanh hai. I am conducting a study to observe and analyze the seasonal variation and prevalence of ticks in cows. The study will involve observation and collection of tick samples from the same 560 cows in each of the four different seasons over the course of a year. Specifically, tick samples will be collected four times in different seasons and once per season from these 560 cows to assess how the tick population varies with the changing seasons. Tick samples will be collected from the same 560 cows once per season, four times a year, to assess how the tick population varies with the changing seasons. Is this good approach or not?
Hi Thaware,
The sample is okay by using the equation provided by Tidjani Ayole Djiman
The data collection approach may increase error if you do not collect the tick sample from the same cow for 4 times during a season.
Just be sure that you will be able to collect samples from the same individual for the duration of the experiment.
To avoid accidental animal mortality and cause problems during analyses, I suggest that you increase the sample size.
For example, for individual number 1 (cow), you will collect tick samples for June, July, August and September 2024. It will be the same for 2025, 2026 and 2027.
Regards
560 cows should be a good sample size for your study, ensuring reliable and valid statistical analysis.