Corn plants from a test plot are measured, and the distribution of heights at 10-cm intervals is recorded in the following table:  

 Height (cm)      Plants (no.)       

100                    20       

110                    60       

120                    90       

130                   130       

140                   180      

 150                   120       

160                    70        

170                   50        

180                   40 

Calculate 

(a) the mean height, 

(b) the variance, 

(c) the standard deviation, and 

(d) the standard error of the mean. 

Plot a rough graph of plant height against frequency. Do the values represent a normal distribution? Based on your calculations, how would you assess the variation within this population?

Video transcript

Hello everyone here we have a question asking which of the following techniques can be used to study the genetics of human height. We have a qualitative studies. Qualitative studies are based on the collection of non numerical data and this includes things like interviews, observations and textual analysis. These studies are useful for perceptions experiences and attitudes, but they are not useful for studying the genetics of human height. So A. Is incorrect. Be randomized controlled trials. Randomized controlled trials are designated to test the efficacy of intervention or treatments. These can include things like drugs and medical procedures but they are not used to study genetics and are not relevant to human heights. So B. Is incorrect. See case controlled studies. Case control studies compare individuals with a particular trait or disease to a control group without the trait or disease. And this is to identify risk factors or associations. These can be useful for identifying environmental factors that may influence height, but they are not specifically designed to study genetics. So C. Is incorrect. And lastly we have twin studies. Twin studies are a well established method of studying the genetics of human height. Here, identical twins who share 100% of their genes. And fraternal twins who share only 50% of their genes are compared for height. And this gives us the relative contribution of genetics. If identical twins are more similar in height than fraternal twins, then it suggests that genetics play a role in height. So our answer here is the twin studies. Thank you for watching. Bye