Melissa needs to buy some pencils. Brand A has a pack of 24 penals for $8.77. Brand B has a pack of 26 pencils for $9.54
1 answer:
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Answer:
Confidence interval = ( 0.7991, 0.8647 )
Step-by-step explanation:
Sample size = n = 351
number of successes = X = 292
Sample proportion = P =
=
= 0.831908831
confidence interval = 90%
Critical Z value = 1.6449 [by using excel]
Confidence interval = P ± Z
Where P = Sample proportion
Z = critical value
n = sample size
Confidence interval = 0.831908831 ± 1.6449
= 0.831908831 ± 1.6449 × 0.0200
= 0.831908831 ± 0.032898
Lower limit = 0.831908831 - 0.032898 = 0.7991
Upper limit = 0.831908831 + 0.032898 = 0.8647
Confidence interval = ( 0.7991, 0.8647 )