Confidence Interval for Proportions with Minitab:

(13) Construct a 95% confidence interval if is 0.48 and the sample size is 250.

(Note, = X/n, so, if we multiply by n on both sides, we get X= n*, n represents the number of trials and X represents the number of successes or the events)

we will use Minitab for this)

Step 1, calculate n*and n**(1-)

Step 2. Check to see if the success failure condition is satisfied, i.e. are the values of n*and n**(1-) 10?

(In Minitab, use the Normal approximation method if both n*, and n**(1-) are 10, if not use the Exact Method)

Step 3. Minitab> Stat>Basic Statistics> 1 Proportion> Summarized Data> No. of events (in this case it is n*= 120)>No. of trials >250>Options>Confidence Interval 95%> Method>Normal approximation>OK>OK

Copy the Minitab output below: