The function P(t) = 100/(1+400*e^-0.15t) describes how to find the percentage of
families who recycle, P(t), in relation to any time t, where t is the number of
years after 1960.
According to this information, what was the percentage of families who
recycled in 1990? (Round your answer to the nearest hundredth.)

Answer options
A: 18.37
B: 88.12
C: 104.44
D: 100.00

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.