Question 1209020:   genetic experiment with peas resulted in one sample of offspring that consisted of 447 green peas and 158 yellow peas. 
a. Construct a 95% confidence interval to estimate of the percentage of yellow peas 
 Answer by math_tutor2020(3817)      (Show Source): 
You can  put this solution on YOUR website!  
x = number of yellow peas = 158 
n = sample size = 447 green + 158 yellow = 605 total.
 
 
phat = sample proportion of yellow peas 
phat = x/n  
phat = 158/605 
phat = 0.26115702 approximately 
Around 26.12% of the peas in the sample are yellow.
 
 
At 95% confidence, the z critical value is roughly z = 1.960 
This is a value to memorize since it comes up a lot in statistics.  
Or this value is something you would look up in a textbook, reference sheet, or website.
 
 
E = margin of error for a proportion 
E = z*sqrt(phat*(1-phat)/n) 
E = 1.960*sqrt(0.26115702*(1-0.26115702)/605) 
E = 0.03500300
 
 
L = lower boundary of the confidence interval 
L = phat - E 
L = 0.26115702 - 0.03500300 
L = 0.22615402 
L = 0.226
 
 
U = upper boundary of the confidence interval 
U = phat + E 
U = 0.26115702 + 0.03500300 
U = 0.29616002 
U = 0.296
 
 
The 95% confidence interval in the format L < p < U is approximately 0.226 < p < 0.296
 
 
This can be condensed to  (0.226, 0.296)
 
 
It indicates we are 95% confident that the population proportion of yellow peas is somewhere between 22.6% and 29.6% 
 
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