An ecologist finds 220 yellow-flowered plants and 180 white-flowered plants. Use the normal distribution to find the Lower boundary of a 95% confidence interval for the proportion of yellow-flowered plants. Which of the following answers is correct to 2 decimal places? a. Lower boundary = 0.30
b. Lower boundary = 0.60
c. Lower boundary = 0.50
d. Lower boundary = 0.40

c. Lower boundary = 0.50

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of , we have the following confidence interval of proportions.

In which

z is the z-score that has a p-value of .

An ecologist finds 220 yellow-flowered plants and 180 white-flowered plants.

220 out of 220 + 180 = 400. So

95% confidence level

So , z is the value of Z that has a p-value of , so .  

The lower limit of this interval is:

Thus the correct answer is given by option c.

answer: c

(2, -4)

goes 7 to the

(9, 4)

easy