Answer:
The Confidence Interval = (0.172, 0.228)
Where:
The lower limit = 0.172
The upper limit = 0.228
Step-by-step explanation:
The formula to be applied or used to solve this question is :
Confidence Interval formula for proportion.
The formula is given as :
p ± z × √[p(1 - p)/n]
n = Total number of red candies = 550 red candles
p = proportion = Number of red candies counted/ Total number of red candies
= 110/550 = 1/5 = 0.2
z = z score for the given confidence interval.
We are given a confidence interval of 90%. Therefore, the z score = 1.6449
Confidence Interval = p ± z × √[p(1 - p)/n]
Confidence Interval = 0.2 ± 1.6449 × √[0.2(1 - 0.2)/550]
= 0.2 ± 1.6449 √0.2 × 0.8/550
= 0.2 ± 1.6449 × 0.0170560573
= 0.2 ± 0.0280555087
Hence, the Confidence Interval = 0.2 ± 0.0280555087
0.2 - 0.0280555087 = 0.1719444913
Approximately = 0.172
0.2 + 0.0280555087 = 0.2280555087
Approximately = 0.228
Therefore, the Confidence Interval = (0.172, 0.228)
Where:
The lower limit = 0.172
The upper limit = 0.228
