Question

The manufacturer of a certain type of new cell phone battery claims that the average life span of the batteries is 500 charges; the is the battery can be changed at least 500 times before failing.

Answer 1

Answer:

A) Here to be 95% confident means we are at least 95% sure that the true value of proportion will lie in the Interval. Suppose if we repeat the sampling 100 times and draw a confidence Interval for each one of them then at least 95 confidence Intervals will contain the true value of Proportion. This is what we mean by being 95% confident

B) Here we have a random sample of 5. The condition of Randomness is met and they are Independent as well because the sample drawn is always Independent. But since the sample size is very small, the condition of a large sample is not satisfied. Either the original sample must come from Normal or the condition of n(1-p) >10 should be satisfied which is clearly not a case here