A science class with 40 students collected data about some of their physical characteristics. When they analysed the data they found that 30 of the students have attached ears lobes and 10 students have unattached ear lobes. What is the ratio of attached to unattached ear lobes? *

Arandom sample of n = 25 observations is taken from a n(µ, σ ) population. a 95% confidence interval for µ was calculated to be (42.16, 57.84). the researcher feels that this interval is too wide. you want to reduce the interval to a width at most 12 units. a) for a confidence level of 95%, calculate the smallest sample size needed. b) for a sample size fixed at n = 25, calculate the largest confidence level 100(1 − α)% needed.