In: Statistics and Probability
Jane wants to estimate the proportion of students on her campus who eat cauliflower. After surveying 29 students, she finds 4 who eat cauliflower. Obtain and interpret a 95% confidence interval for the proportion of students who eat cauliflower on Jane's campus using Agresti and Coull's method. LOADING... Click the icon to view Agresti and Coull's method.
Solution :
Given that,
n = 29
x = 4
Point estimate = sample proportion = = x / n = 0.138
1 - = 0.862
At 95% confidence level the t is ,
= 1 - 95% = 1 - 0.95 = 0.05
/ 2 = 0.05 / 2 = 0.025
Z/2 = Z0.025 = 1.96
Margin of error = E = Z / 2 * (( * (1 - )) / n)
= 1.96 * (((0.138 * 0.862) / 29)
= 0.126
A 95% confidence interval for population proportion p is ,
- E < p < + E
0.138 - 0.126 < p < 0.138 + 0.126
0.012 < p < 0.264
The 95% confidence interval for the population proportion p is : (0.012 , 0.264)
A 95% confidence interval for the proportion of students who eat cauliflower on Jane's campus using Agresti and Coull's method is between 0.012 and 0.264.