Question

A farmer wants to estimate the average growth in height of his corn plants over a two-week period. Of his 5,000 plants, 1,500 are on plots where he grew corn last year, 3,000 are on plots where he grew soybeans last year, and 500 are plots where nothing but grass grew last year. The farmer wants to use a stratified sample of 200 plants based on what grew on the plots the year before. How many plants from plots where he grew corn last year should be included in his sample? Enter a whole number.

Answer 1

60

Explanation:

Given that :

Total crop on corn plot = 1500

Total on soya bean plot = 3000

Total on grass plot = 500

Total plants = 5000

A Stratified sample of 200 corn plants is to be selected ;

Number of samples he takes from each plot:

Percentage of number of samples :

x% of 5000 = 200

0.01x * 5000 = 200

50x = 200

x = 200/50

x = 4%

Hence, number of plants to be selected from corn plot :

4% of 1500

0.04 * 1500

= 60