The student officers are buying packs of streamers and balloons to decorate for a school dance. Packs of balloons cost $3.50 and packs of streamers cost $2. If the student officers bought a total of 12 packs of

decorations and spent $31.50, how many packs of balloons did they buy? How many packs of streamers

did they buy? Write the solution in a complete sentence.

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.