Tessa places a 10 m long ladder against a tree, with the base of the ladder 3 m away from the base of the tree.
Using Pythagoras' theorem, calculate how far up the
tree the ladder reaches.
Give your answer in metres (m) to 1 d. p.

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.